I'm aware Fareghus is a far from perfect nation. It is a nation born from the descendants of Andrestia, who rebelled to form a kingdom of their own. Its people still have colonialism and imperial culture at their roots. It has a lot of issues to work out.
And I believe that the next generation, the ones who are coming into the lead of their people, are going to be the ones to break the cycle. Not all of it, not right away, but they are going to be future leaders, and are aware of aspects of their system that are hurting their citizens, and want to change things. I don't think you can like the characters of Faerghus sincerely without recognizing the problems of Fearghus as a nation. Dimitri wants to end the racism against the Duscur, Felix loathes the culture that promotes venuration of death, and a bunch of them definitely have problems with how views about crests have impacted their lives.
And they don't want to burn down the whole system. They want to change it from within, from what they can do as lords of their people. And defecting breaks the trust of the people in them, hurting the causes they desire to change within their home.
Edelgard wants to change the system too. She wants to burn away the old, and set up a new one. And while I agree that fire needs to be set for the sake of progress, that destruction is a bringer of change, it should not be what you bet it all on. Everything set on fire, offers no means of escape, and you need people to keep things running. I know she needs to move fast, because she has a time limit, but all that fast moving does not ensure a stable structure being set for the future she is trying to build, she doesn't have a system set in place to keep the future she is building up to, to continue to get there after her death. The cost is already a lot of lives lost to the war. The commoners who lost resources and people to it , the soldiers who fought in it, the leaders who died defending what they felt was theirs, the land that is scarred by it. Who is going to be there to keep the people from reverting to how things used to be after her death?
She has no heir/sucessor, adopted or otherwise.
She is descended from an Empire of conquests, and it is still active as seen with Brigid, and Dagda. And she solved the problems that came the same way? Is she going to have the diplomacy to ensure lasting peace for future problems? Particularly as she was kept isolated by the tunnel snakes who have racist (speciest?) Views, and only in a route where Byleth helps her, can she break away from them. And that help comes at the cost of Byleth alienating their own support base, the church.
But back to Diplomacy, after conquering the continent, and Killing the tunnel snakes, she probably has to deal with Almyra, particularly if she killed Claude. Regardless of how much the people of Almyra like or dislike Claude, she still (unknowingly, as he has trust issues for good reason), killed a royal of another country. And Almyra does not have a good relationship with the Leicester already, the now Empresses of the continent killing a royal of your country seems a good reason to invade. Especially since the continent is still pretty rocky after all of the invasions she did, hey allies, let's go hit them while they are down.
The earlier invasions from Almyra in imp year 961 was barely defeated after all, and threat of further invasions was what prompted co-operation. But I don't expect fantastic cooperation from a nation that has recently been conquered. Tropes, resource management, and morale are not going to be at their best or most cohesive under the circumstances.
So she could potentially be fighting a two pronged war, if they decide not to wait for her to finish dealing with the snakes.
And even if Claude lives, he's not exactly in a good position to prevent a war, should they decide to go for it. And going to war in a recently conquered, unstable continent, are pretty good odds to expand Almyra, at the least, if not necessarily total victory over Fodlan.
I don't think Edelgard, as Empress can have lasting peace under the circumstances. Change certainly, but not peace in her lifetime or the aftermath. And I do think, that if her chapters had been given the full length and attention the others had, it could have been a fascinating avenue to explore this kind of conflict.
*Hopes Edelgard may be different, but I can not accurately say until I experience it, either through luck of finding it used at good price (increase in digital gaming makes that a taller order then it used to be), or watch a playthrough. Currently watching Majin Tensei 2 movie, and thinking I might want to watch a lets play of SMT 4 instead of game movie, so might be a bit.
