You're asking for content that is specific to one, very very small player preference.
That is not true. You just have to look at any big reddit thread about this topic from after Patch 6 was released to see that a vast majority thought the old expressions made perfect sense.
Neutrality allows for infinite RPs and HCs. Specificity is limiting.
I would agree, but the new expressions really, really don't look neutral to me. Tav's face at the throat grab looks like it was taken straight out of a sex scene. The smirk after their face is shoved away is not neutral either.
If Larian were to add an option for how Tav reacts to OPTIONAL kisses with AA, then they would have to do it for ALL the characters.
No, they wouldn't. AA is the only character that has different reactions for Tav already existing in the files. Asking to add back content that was removed after being in the game for half a year is not the same thing as asking for completely different animation sets to be created based on someone's personal hc for a romance path.