Like, ok. Consider: what is Dragon Age?
At its best, it is a story about morally complex characters. Villains who are capable of great virtue, whose motives we understand and empathize with even as we condemn the atrocities they commit. Heroes who have deep flaws, whose prejudices and failures have consequences that echo for themselves and everyone else.
At its best, it's a story about rich, thoughtfully-rendered factions, each with their own histories and perspectives and beliefs, whose pursuit of self-interest leads them into conflicts; a story where the protagonist navigates between those factions, and makes decisions about who to support, when to reconcile, when to strike out.
At its best, it's a story with a complicated, mysterious backstory of strange magic and eldritch powers that shaped the world long ago and still echo forward in ways that are poorly understood and inspire wonder and curiosity... but which keeps, in the foreground, far more relatable, mundane questions of the small lives of normal people and the vast and complex modern politics that govern those lives.
A murderer, a savior of heroes, a mother who deeply loves her daughter but also abused her for twenty years to attempt to turn her into the same monster who raised her. A woman responsible for the death of half a terynir and also essential to the salvation of multiple nations. A human and an elf and a spirit and a mortal and none of those things, deeply intertwined with the history of the Dalish clans, their city-dwelling ancestors, and the most powerful human nobles; someone who no one would be the least bit surprised to find was deeply involved with the dwarves or Avaar or qunari or anyone else, as well, because that's just how she is. Someone woven into the very fabric of the setting, a creature out of the ancient lore of elves and the founding of the kingdoms of men, but also just a crazy old woman in a swamp. Someone equally invested in heroes who shake nations, and irrelevant refugees who can do no more than watch their cities fall apart. And also, not for nothing, someone who is a fucking dragon.
In other words, Flemeth is Dragon Age. She is the distillation of the entire franchise into a single obnoxious, charismatic, meddling, necessary Q figure. She could cameo in every game forever, in any scenario, doing anything to support or interfere with any protagonist at any level of relevance, and it would always fit. She would always belong there.
And it matters, here, too, that she's a woman who holds this role. That the most powerful and knowledgeable figure in the setting, someone who can only be begged from or bargained with, someone who can't be meaningfully punished for her crimes, someone who is strange and important and unrepentant and holds all the secrets and can't be compelled to give a single one before she's ready, is a woman. This is not a role, even here in the year of our lord 2024, that women often get to have. Back when Origins was made, it was even more rare (Origins itself has enough gender problems that it was remarkable even by Dragon Age standards that this happened at all).
But with Veilguard, the devs made the choice that Flemeth's last act, whatever she was doing with the Eluvian in that scene, was just flavor text rather than the creation of some phylactery such as she gave to Hawke; that her last words to a player character, a promise of future vengeance and a plan yet in motion, should have no meaning or fruition; that the smartest and most cunning character in the setting had no backup plan and was totally blindsided by being betrayed by the god of betrayal; that a woman who has repeatedly failed to die to the most dramatic defeats is, indeed, just unceremoniously totally fucking dead to a simple knife in the gut; that all that should continue of this character into further games is a broken fragment of one part of her complex construction, a pale shadow with no power, no agency, no wisdom, and no purpose other than begging her own murderer to stop being a dick so he can get a happy ending; that Flemeth is no longer needed in the story, and that her role of eldritch manipulator henceforth should be filled by said murderer instead.
And okay, sure, for what it's worth, Solas is also a really well-drawn morally ambiguous character. He has all the same moral depth as Flemeth. But I shouldn't need to tell anyone how unremarkable it is for a dude to be written as a sympathetic bad guy who gets to get away with his crimes and be crucial to the heroes' story because the fans like him. And that's the only criterion he meets. Solas has no connections to any living faction - not only does he have no interest in any political grouping of humans or dwarves, his active disavowal even of modern elves is a crucial character trait in two different BioWare stories. He is deeply bound up in the ancient backstory and lore, but he has no interest in any mundane part of the setting, be it people or politics; it is in fact a core character trait that he refuses to even consider any such connections in order to preserve his own motivation, and the plot politely offers up the contrivance of his restriction to Rook's brain to turn that preference into an unchallengeable physical fact.
Hell, they even make a point of him being the only Evanuris who doesn't have a goddamn dragon!
But maybe it's not surprising that the pathetic whimper of a torch-passing from Flemeth to Solas came hand-in-hand with the abandonment of any depth to or interesting conflict between factions, any real flaws or moral complexity to the characters, and any real pretense that the political conflicts we faced had even half the relevance or meaning to the writers as the bombastic mythological conflicts. Flemeth is Dragon Age. And in many meaningful ways, Veilguard simply is not. Perhaps it was inevitable that she would have no place there.