Well I expect a lot of people to dislike my comment, but here's what I think.
I think it was awesome that you could choose to be with Triss in The Witcher 1 and 2. Nothing should have been changed there in my opinion. Why not? Because it makes sense. Geralt doesn't have his memory and the little stuff he could actually remember counted positively towards Triss, plus... Well... As always, she was also "trying her best" when around him. "My Geralt" went all in with her and I would've done it again.
However, after finishing TW2, I took my time to read all the books, and with this new found knowledge, I know what should happen should Geralt regain his memory - which he does in The Witcher 3. Don't get me wrong, I'm not bragging or anything, after all anyone that likes the story can read the books through the fan translations present in these forums (provided they know english). All I'm saying is, once you know the full story, it just wouldn't make sense for Geralt not to pick Yennefer. Saying they went through a lot together would be an euphemism.
Long story short, now that he actually has his memory back, he can't just ignore all that happened with Yennefer. If anything, limiting Geralt's choice to her should only encourage players to read the full story - and if they don't want to, there's no problem with that, but at least they should have to understand that is who the main character is. This isn't Skyrim or Dragon Age: Origins, where you literally make your character and shape him into whatever you want (nothing wrong with that, just mentioning those games to prove a point). Geralt already exists. In a fictional world, of course, but he does. Getting to choose how he acts towards certain incidents and what he says in conversations is really awesome and understandable, I dare say one of the best things about this series. But this specific choice between the two girls is just too huge considering his past.
So hate me if you will, but I must say, I actually have my fingers crossed hoping we CAN'T choose Triss. It's clear by now that you will be able to have a relationship with her through the game, but should there be a final choice... Yennefer is the way to go.