I do see your point, but the "take the place in Avernus for herself" route is hardly in-character for her, no matter how you slice it
General revenge - maybe, sort of (although it doesn't really satisfy her, as Gortash shows), but power doesn't seem like her style. And I wager none of us really want to see the character herself re-written - we love her for a reason, and her being different from the other companions in terms of her struggle is part of that reason, I think.
I'd say in her case the routes should me more equal in terms of "likely to happen", rather than reasons.
As in, I'd say the 'best' option should be hard to get and easy to miss or screw up, so that the 'bad' routes still bear significance. Well, that - or maybe the price should be steep, so the player theoretically has motivation to NOT go that way?
I mean her character WAS re-written in the new avernus ending to some degree, where she suddenly goes full action hero, doomslayer mode and wants to take the fight against zariel despite adamantly stating throughout the game that she never wants to return to avernus. Not only did she not seem too bothered about being back after everything she said, but shes ready to march against zariels forces cigar in mouth. Its very. Strange.
I wouldnt personally be fully against this characterization, but its very jarring now as it is because we dont have any dialogue that explore this side of her. The idea aron presented of letting us choose between stabilizing or powering up her engine, and the latter leading to her becoming more angry and vengeful and wanting to take the fight against zariel(without necessarily wanting to take over zariel), is one way to make this characterization work.
