I like that idea, but if it is too much to ask, then at least have Triss get mad at Geralt and Yen, and have her demand an explanation from Geralt (and Yen). When I first saw that scene, I was like "uh oh, Geralt is in trouble", then Triss never mentioned it ever, which was disappointing.
Agreed, it was all perfectly placed for something to happen after, but nothing came of it and i think a lot of Triss fans in their first playthrough would of been angry and the kiss and then were probably thinking this would lead to something, and i was looking forward to it but nothing happened, which is disappointing (to say the least).
I also got the feeling it was part of the Yen romance first and foremost (i could be completely wrong when i say this), but looking back it seemed like it was a scene designed for Triss to have a reaction because she was the ex-lover rather than the current lover.