I tend to disagree, and I do think there is a problem with the writing. I for one didn't follow the marketing, and, believe it or not, I didn't know Astarion was a Vampire. Or whatever was up with Wyll or Shadowheart. That aside, let's focus for a moment on Astarion. So you find him, and maybe after some sort of misunderstanding you agree that it is better to work together. We both have a bloody tadpole crawling around in our head, and we both agree that we need to remove it, and that our best chance is to work together. Fair enough up to that point.
So what does he do? He sneaks up on you one night and tries to drain your blood. No matter what he says afterwards, he has proven that he is entirely untrustworthy. Given the situation I'm in, I'd kick him from the group. I have enough problems as it is, I don't need a Vampire in my group that I cannot trust (okey, that seems to be redundant).
As for the others, Wyll and Gale are completely overdone. Their backstories do not link up with what they actually can deliver. Shadowheart and Lae'zel are better in that regard, but swing between arrogance and rudeness. I don't expect them to be particularly nice to me, but given the situatuion, and the fact that we apparently agree that we are better off as a group, I expect something more civil.
So I do have a problem with the writing. So far it seems to me that Larian was trying to outdo what they had delivered in DOS and DOS 2, but they overshot the target.
You can actually kick him from the group.