Even if you don't there is no excuse either... Only reason for her not to be there is if you don't help her out with her quests as she might still be trying to get the mages out. Actually that's no reason either, as she does eventually come at "yennefer's" behest and leaves the mages to their fate. So in the case that you don't help her, she could be still in Novigrad and you ask her to come to help lift the curse that should auto fail her quests (and destroy any chances of romance, same as Yennefer if you don't help her out).
Ego. Remember what Geralt says towards the end of Ugly baby? Words to the effect of "
If we contact Triss for help before Yen's failed, she'll be mad." Yen's ego precludes her asking for Triss' help prior to the Battle of Kaer Morhen, so yes, there is good reason for Triss not to be there if not romanced. However, if Triss was there due to being romanced, Yen would naturally involve her (and just as naturally assume she was in charge, delegating tasks to Triss like the others) so the scene works without a major re-write. It just needs tinkering around the edges.
Romances aside, this is a story about a father looking and then protecting his daughter. And him using every ally and means available at his disposal towards that end. Geralt not relying on Triss to help just because he says "Let's try again" instead of "I love you" is just wrong.
I mean, in the books she came when she was asked for help. And the situation is both magical related and dire enough for Geralt to recruit all the "magical" help he can get. The only sorceress he can rely on are Yennefer and Triss, so naturally, in a matter so important to him (his daughter) he would get them both on board.
I understand and share some of the complains in the Yennefer thread about missing interactions, especially at the beginning in Vizima and the lack of Yen/Ciri moments, however story wise the situation with Triss is worse as they actually went out of their way with the narrative to keep her out of it. One example is the one I described above, another is that Ciri just "couldn't" find Triss when she was looking for her there, and, somehow, Dandelion couldn't either and again, their problem was magic related (they needed help with the Philactery).
The more I think about it, the more I think what I shame it is that the romance angle as originally intended (Triss leaving for good and Geralt reuniting with Yennefer) got in the way of good and consistent storytelling.
Whilst I agree with those in the Yen thread, and have said so myself many times that Romance, as a story telling and game mechanic in
The Witcher 3, is fundementally broken, I disagree that it was a shame they put the Triss romance in. It might have worked as a stand alone game but wouldn't have been accepted by those who've played the previous games and romanced her as part of their choices in them. What should have happened is Triss and Yen romances were both properly written from the get go and not had one thrown in haphazardly as an afterthought at a later date. Had both been properly written and treated with equal respect, the story would be a lot less muddled with a lot less plot holes as it is now.
Frankly,
The Witcher 3 has a big problem when it comes to its writing because it tries to be the final part of a trilogy, whilst being a stand alone game at the same time. It tries to accommodate the old guard whilst trying to be new comer friendly. It attempts to reconcile those who have read the books with those who haven't and as a result of all these contradictions, large parts of the story end up being neither one thing nor the other. Really, CDPR should have forgotten about pleasing everyone and just remained true to themselves. The writing would have been better for it.
Don't misunderstand me, there is great writing in this game, there's just not consistently great writing throughout, being interspersed as it is with moments of utter confusion (i.e. plot holes). This game is genius, it's just flawed genius, sadly but some attention to detail, some cleaning up of the story here and there, released as part of an enhanced edition and you could fix the problems fairly easily. They just need the will to do that.
