I'm going to agree with something starryophonic wrote, which is that relationships can be complex without introducing problematic content.
I'll also out myself somewhat by stating that I am a submissive and a masochist. Most of the time, when I see kink portrayed in media (be that literature, video games, or what have you) it's poorly done and misrepresents how much of a role consent, trust and negotiation between partners plays in the relationship.
I think it's fair to say that Astarion (UA and AA) touches on themes of dominance and submission, but without fully engaging with them (the game flirts with the subject, but doesn't explore it beyond a few winks). I think it would have been interesting to embrace the subject more, with Tav and Astarion having at least a conversation about preferences and boundaries.
One of my gripes with UA has always been that he turns fairly vanilla, as if the kink was just part of his act. Which bothers me on several levels. At the most basic, there's a subtle implication that kink is somehow 'wrong' in that only an evil character would partake. It would have been nice to see UA and Tav engaging in some dialogue about what he enjoys/wants to explore now that he's decided a physical relationship with Tav is back on the table.
