While I agree with most things you said, I just can't consider the current state of Triss romance horrible, its flawed yes, but horrible, never. There are so many moments in the game that made me love Triss, just the way she looks at Geralt at certain situations is amazing to me, her voice, personality and how obviously she is in love in with him, make her head and shoulders above any romance option in any game EVER, in my opinion of course. With the few scenes she has CDPR has set the bar so high that I am simply disappointed that there aren't more and that the game sidelines her after all those amazing scenes.
Just the fact that it has made me care this much about a fictional character speaks volumes to me, if it was completely horrible I wouldn't even bother coming here daily, discussing about her and hopping for more content. Never in my life have I cared about imaginary character enough to want to invest a fraction of the time I am "wasting" here every day, slacking off at work and in my private life just so I can read all the things posted here. So I think that Triss romance is not at all horrible but amazing, it just has certain inconsistencies I would like to see fixed so it can be even better.
As far as sex scene is concerned, I agree it is not the best, especially after the elven bath has raised the bar so much, but it doesn't bother me that much, I would rather have more dialog with her, and if they decide to change it or add another sex scene, that's fine.