It's not that I don't understand that they're on edge and it'll take some time to establish a good rapport. It's that these NPC's in particular are just not well written. Their backstories are too wild. If I showed up to a gaming session and my co-players had written Wyll, Gale and Astarion I would be dumbfounded. Lae'zel and Shadowheart are better, but they're still unreasonably unfriendly, what with us trying to get out of this thing alive together.
I think it's on purpose. I believe what Larian is trying to say by giving all the companions unique, out of the ordinary backstories is that they were purposefully selected by the "Absolute" and that the abductions weren't random. The biggest question is, can they make the MC's backstory just as unique? I certainly don't want no God Chosen crap from DOS2. That's what's really missing right now, is the backstory of the MC. Without a backstory, the companions "outshine" your MC and I think that's what a lot of people don't like. That's what I believe anyway.
On the topic of the post though, the only character I don't really like is Shadowheart....and that's ok. Can't like them all. You're bound together through necessity, not because you want to travel together and I do think that comes across quite well. Unfortunately it seems a lot of people expect an adventure among friends experience. I actually like more stand-offish characters - at least in the beginning - because it just makes more sense in the world setting. Once you get to know them, they soften up. Though I do agree that the companions introductions could be done better. Lae'zels, Shadowhearts and Wylls were fine but Astarions is off especially when you approach him from the direction of the supposed "Intellect devourer" and Gales is just cringe.
The only thing I don't like is that the companions only really interact with your character if you travel with them rather than them being in the camp the whole time. Whilst it's realistic, it's not great from a game perspective because you miss out on content with those companions and they don't give you enough time/information in act 1 to make a good decision on who your final team will be. I'm sure that's something that will get cleaned up on early access.