I think this entails some unrealistic expectations of the Aes Sedai and a general misunderstanding of what they are, and what the Ajahs are.
So, aside from wearing red dresses and being idle, the Red Ajah does very little work
This is the misunderstanding I am talking about. The Red Ajah are not the male channeler police. They are Aes Sedai who think that stopping male channelers is the Tower's most important job. Not its only important job. They do NOT sit around waiting for male channelers to pop up, rather they go on with all the other stuff that a woman might do who holds an enormous amount of power, wealth and social influence. And that's going to be a lot of different things. Because power, wealthy & influence give you choices, so the Aes Sedai are free to fully be themselves more than just about anyone else. What they are not, is soldiers or other ready-response minions sitting around a ready room awaiting a call to action. What do the Red Ajah do if there are no male channelers to fight? Well, just look at the first Red sister we meet. Elaida is the OG Red, from the readers' perspective, and how much fighting of male channelers do we see her doing? How does it inform any of her actions on the page? The other Reds are doing what Elaida does - working on things they think are important, helping the world or getting their kicks.
And the same goes for all the Aes Sedai. That is the point of the Tower, to give sisters the support and power to go out and do whatever they want, whatever they think needs doing. It's not an army or a government or an administrative organization or a school, it's a guild, that is established for the protection and benefit of its members and the craft they practice.
Aes Sedai seem more focused on creating an image of themselves as legendary, scary, and influential figures rather than truly being that way.
Because the perception of power is power. People listen to the Aes Sedai and obey them, because they believe the sisters are legendary, scary and influential. By contrast, look at how Gedwyn behaves toward Rand at their first encounter. All of Rand's knowledge, power, authority and resources do not impress him or get Gedwyn to treat him with respect, because Gedwyn does not believe Rand has that much more power than he himself. If Taim had not intervened, it would have forced Rand to exert force on Gedwyn in order to get him to do anything. Basically, a fight. This is why the Tower cultivates this perception, so they don't have to fight.
Three Oaths are not only meant to minimize people’s fear of them, but they also serve as a convenient way of “doing nothing.”
Yes, but doing nothing is more powerful in some ways. That's why the Aes Sedai do it. The First Oath gives them the benefit of credibility without having to back it up. The boy who cried wolf lost his credibility, so that no one came to his aid when he was truthfully warning of danger, but an Aes Sedai never has that problem, no matter how many false alarms she sounds, no matter how she manipulates people. She can always say "There is a wolf approaching. I can see it. It is an immediate threat," and people have to believe her. And because the sisters have to be very very careful of their words thanks to the Oath, it also means that they are very careful about commitments, as is the intention of the Tower.
That is the real motive for the Oaths, to protect the Tower from commitments and the pitfalls of being on a side. The Oaths allow the Tower and the Aes Sedai to both sidestep and transcend geopolitical struggles. By cultivating their reputation for indirect speech, and not wielding the One Power as a weapon, they have the reputation for indirect action, and conceal maneuvers. And that means you can never be sure what the Aes Sedai did or did not do in any political situation. It gives them the ability to disavow any losing side and claim ties to any winning side. We see this in action with the Aes Sedai speaking to all the nobles in Cairhein and Caemlyn in Lord of Chaos, and Annoura's behavior toward Colavaere in the subsequent book. The Aes Sedai are not "up to" anything specific in either city. They have no political scheme or agenda in mind, no greater plot. All they are doing is creating the impression of doing things, of being in control, because in each case, they intend Rand to remove himself from the governance of that country, and for the status quo to resume. The Salidar gang want to put Elayne on the Lion Throne, and getting Rand out of Caemlyn is the precursor to that, and the Tower embassy intends to bring Rand to Tar Valon, in which case they want things going back to normal in Cairhien. They are not committing to any side or scheme, which is why they are talking to members of all factions, just basically giving enough hints so that when Rand is gone, people will believe the Aes Sedai did it.
You might think this is all fake and "doing nothing," but what it does is store up Aes Sedai influence and power for the really important things. In theory, when the Shadow or some other external force that is a common enemy of all humanity, or at least the macro-culture and civilization that consists of the western/wetlands portion of the continent and is affiliated with the Tower, strikes, the Tower will be in a position to exert leadership. People will listen to the Aes Sedai in these situations precisely because they not firmly locked in to any faction. They hold themselves apart from the politics and they don't let you know what they are doing or where they stand, so when it's really important, you have no reason to see them as part of your enemy's faction, no reason to suppose this is all a trick to get you to lower your guard.
This characteristic of the Aes Sedai is their version of Saldaea, Shienar et al keeping their armies on the Blightborder, rather than marching south to conquer other lands.
“Tower is first” is a great excuse ... to avoid helping people directly, for example, by creating hospitals where they could heal the poor.
Explain how that is supposed to work. There were about 120-130 Yellow sisters in the Tower. Spread them around to all the nations, that's ten sisters to a country. Put each sister in a hospital all by herself and she can Heal a few people a day, and meanwhile, it's several days journey to the nearest other Yellow hospitals. And meanwhile, that means that every Yellow is now locked down for life. Political interests? Studies? Fighting enemies that need to be fought? Wielding influence in the White Tower so as to have some say in how things are done? LOL. Nope. We're already critically undermanned, back to the grindstone, sister!
Same deal with stationing the Green sisters along the Blightborder. How does that work? Do they take charge of the defense of the border? Do they place themselves under the command of the military authorities? Either way has bad implications for the Aes Sedai and their relationships with the rest of the world, and as with the Yellows, it narrows these women's lives down to a single purpose.
The irony is, people with these expectations of the Aes Sedai are the ones who are failing to appreciate the humanity of the people they are talking about, and instead seeing them as pieces on a game board. Hell, they are being worse than that. This is like playing Warcraft III and using your hero unit to guard a particular approach to your base, instead of taking advantage of the unit's varied powers, and ability to improve by leveling up. You don't even use them that way on the missions where there is a ticking clock and you have to hold the enemy out until it runs down. An Aes Sedai is a hero unit, and you don't waste them on limited tasks that ordinary units can handle, you use them to respond to major threats, and to bring the attack directly to the enemy.
not to participate in foreign conflicts
Oh really? How does this work? How do the sisters not participate in foreign conflicts? What is the definition of participating, or of foreign conflict, for the purposes of this discussion? Foreign to whom? Foreign to Tar Valon? Foreign to their homelands? Or do you mean international conflicts? Because by everything we see in the books, the Aes Sedai very much participate in international conflicts, and, in fact, end them. Do you mean fighting wars? On which side? Because that's the thing about conflicts. They have sides. When you participate in a conflict you take a side, and by any sort of aspirational standard, not just political cynicism, taking sides is not appropriate for the "Servants of All". From both the perspective of the greater good and the playbook for securing their maximum soft-power influence, the Tower should not be lining up with Murandy to assert that they are in the right in their tariff policy toward Altara, or going to war beside the Domani against Tarabon.
you shouldn’t expect Aes Sedai to travel the world helping people.
Because when you expect it, you gain a sense of entitlement to it, and that gives you license to judge the Aes Sedai and criticize them for failing at their side project that just so happens to be more important to you than it is to them.
There are Aes Sedai who work as advisors to queens/kings or who take part in negotiations between nations...it gives them more power and influence, and it doesn’t significantly change life in the Westlands.
How else do you change life without power and influence? Changing life is much more complicated than a single woman performing a single task. Changing life is an ongoing, widespread effort that requires a lot of power and influence, that can be wielded by an institution capable of long-term goals, rather than an individual's idiosyncratic wishes and focus.
I believe the Westlands live in more or less stability, but it’s not because of Aes Sedai power. It’s more due to their lack of it. The laziness of the Aes Sedai, along with their focus on influence, position, and privileges, doesn’t do much to improve the lives of ordinary people.
There is widespread literacy throughout the lands under Aes Sedai influence. While there is poverty, the only place where we really see grinding desperation or people starving, is in places in crisis (e.g. Tarabon), or in Tear, which rejects Tower influence as much as possible. Meanwhile, war is very limited in both scope and scale, to such a degree that military organization, technology and tactics are greatly behind where they are in the real world. IRL, gunpowder was introduced in Western Europe about 100 years before small portable clocks, such as one can find on the mantle of the village inn in Emond's Field, at the ass end of nowhere. That same inn also has a small bookcase full of books, where in the real world, before the printing press, kings might have a library that numbered in the single digits. That same printing press was also a long time in appearance after gunpowder. To put it bluntly, the world of the Aes Sedai is one where clocks and books are in greater supply and demand than gunpowder! It is a world where women are equal to men and have as many opportunities, and where military might is not the ultimate power. It is a world where poor women's bodies are not exploited with systemic prostitution, nor are rich men's daughters & sisters traded like cattle or reduced to ambulatory wombs. There are arranged marriages, but these are depicted as entered for personal gain or as part of the individuals' commitment to the political goals of their faction or nation.
You say the Aes Sedai don't do much to improve the lives of ordinary people, but that's because you don't know much about life in a pre-industrial society and can't recognize how good life is in the wetlands, or you have been conditioned to associate the phrase "improve the lives of ordinary people" with specific actions, in accordance with the perspectives of certain political IRL ideologies or economic systems, that is, building hospitals and schools and handing out material goods. But that's political, that's the Aes Sedai stepping off the elevated position they have erected in order to protect the world from paranormal threats, and mixing it up with everyone else, and making enemies and becoming just another faction, rather than Servants of All. Because if you're going to undertake those kinds of direct materialistic assistance, you're going to need to make decisions about resources and where they are allocated and who gets what, and that is going to mean pissing people off and depending on other people for stuff, that still has your name on it, and so now you have to answer to other people's actions.
Now all of this is not to say I am an Aes Sedai stan or that I believe they are in the right. I do think they are more concerned with their power than doing the right thing. But that's the natural outcome of concentrating on gathering power or resources in preparation for a future need - when that need does come, very often the habits of gathering, keeping and saving interfere with your willingness to use those resources or power for the original purpose. The Aes Sedai are very used to doing things a certain way, because that is what their experience has taught them is the best way, and their success proves them right. But all of a sudden the game has changed, and their practiced moves and tested strategies no long apply. The only true thing in Moiraine's farewell letter to Rand was the bit about how the Aes Sedai are too used to their old habits to adapt to the new reality with Tarmon Gaidon on the horizon and the Dragon Reborn running around.
The Aes Sedai do seem to be responsible for the stability of the land, but that stability is turning into stagnation. The very lack of war, lack of conflict, which has saved so many lives under their aegis, means that the people of the wetlands are woefully ill-equipped to fight people from outside the Tower's influence. It means that the combined civilized nations got their asses handed to them by barbarians whose forces consisted solely of light infantry, and it means they are no match, militarily speaking, for the Seanchan.
But this sort of thing is not because the Aes Sedai in particular suck, that's just the nature of human institutions. They become self-perpetuating and lose the plot. If the White Tower was different, if it used different methods and practices, its flaws and faults would be different, but there would still be flaws and faults, still be problems with their ability to respond to the threat of the Shadow, and the world would still need ta'veren to shake people out of the ruts and the boxes that their society and all of its institutions put them in.
There is plenty to criticize the Tower and the sisters for, but IMO, most of it is in the area of failing to accept or acknowledge that they have power and have a responsibility to discharge it by making active and conscious decisions, rather than continuing in their old habits and established ways of doing things, just because it relieves them of some of that responsibility. In other words, where the OP quibbles over the direction of their institutionalization, seeing only what the organization is not doing, and what they could be, the real issue is their being institutionalized in the first place. Debating the best use of the Aes Sedai manpower and what activities they should be undertaking is rearranging deck chairs on the Titanic. What they should really be doing is learning to swim.