I wish that the only problem with Triss was the change of her look.
I always felt that the point of Triss was that she was supposed to seem quite young / playful / lighthearted in contrast to Yennifer (who has a more stoic/powerful character) and I don't feel like we saw any of that, but then, there was hardly any Triss at all in this and I'm basing my perception of her on the games, which are set after the books so 10+ years after the events we've just seen in the show (e.g. Ciri is in her early 20's).
Of course, there was the slightly problematic fact that (Witcher 2 spoilers)
Spoiler:
Triss was essentially date-raping Geralt for the first half of TW2! bit of a darker side to her there.
For those who haven't played it; Geralt has memory loss at the start of the game, he knows who he is etc. but he doesn't remember Yennifer or their relationship... he's travelling with - and in a sexual relationship with - Triss... who of course DOES know everything, but doesn't tell him about Yenn and tells him he's with her and carries on lying about it because she doesn't want their relationship to end. He's understandably not too pleased when he eventually remembers