Another thing I wanted to bring up regarding playing as Astarion is romance.
Astarion's initial reason for romancing anyone is manipulation. This is unquestionable. His view on attraction and affection is utterly skewered, after being forced to perform it for two centuries. And let's not forget he was horribly punished when he allowed himself to feel something. Sure, Cazador actually punished him for running away, but in Astarion's mind, feelings = torture. Love and sex are a means of manipulation, nothing more.
When you play as Astarion, there is no need to manipulate anyone, because you're already calling the shots. It is actually a relief for him. He doesn't need to use his body and he doesn't need to fake affection. He can definitely fake friendship, so he could keep all (or at least some) companions as a shield that protects him, but that is completely different from resorting to use himself. If companions attempt to flirt with him, he will only be reminded of what he was forced to do for two hundred years. He might flirt back in a teasing manner, but I can't really see anything serious in it. And let's face it - followers themselves are crap at seduction. The player is always doing most of the work.
(Not to mention the utter tragedy of Zethino's "test of love", where only the player is actually tested while the other side does literally nothing except approve of disapprove. Seriously, Larian, that whole thing is bloody awful. I can almost see Astarion telling the dryad where she can shove her test and demanding his money back.)
In other words, player Astarion isn't interested in romance. At all. And companions can do nothing to warm up to him because they aren't properly interested in HIM in the first place. They are interested primarily in the outcome of their own personal affairs.
