To change the subject for a tiny moment - and yes I don't like the facial animations either even though I don't like the ascended path. I don't even think they fit the promotion material because our dear rizard has danger kink and thinks AA is hot ...
I have previously thought that Astarion's spawn romance works better for Gale than Gale's own romance arc does and I am more and more affirmed in the opinion that that the same holds true the other way around. It really for the most part boils down to player dialogue. With Gale you share mutual admiration. While there are pearl-clutching-paladin dialogue options, there usually is one that shows support for him, even when you disagree with his plans, and when you talk him out of the Crown, you can do it out of concern for him. You can be each other's none judgy biggest fans, swapping sincere sounding compliments and be supportive of each other in times of doubt. Like, well, like equal partners who adore each other and are each other's strength.
The PC for Companion Astarion is rarely allowed to be emotional, vulnerable or allowed to tell Astarion how incredibly marvellous he is, just the way he is. So you have Astarion's beautiful dialogue on one side and the wooden player dialogue on the other and that just doesn't work well to perfectly create this "together" feeling that I think the romance should have.