Larian has confirmed that for now they wanted to put out the more evil type companions. They said that normally people want to play the Good guys, and in most games that is the only route to satisfactory results or interesting gameplay. But in BG3 they wanted to allow more different playstyles and hence the first characters you see in EA will more likely lead you to those different playstyles to see that "hey, this works as well". Good guy companions will be coming to the game at some point.
This info is from the twitch.tv chat with Swen. Link is in his twitter.
keep in mind, I'm not complaining about the companions being "bad" I have ZERO issues with bad guy companions, Edwin and Viconia are, just for example, absolutely BELOVED characters, but rather how heavy the special status of the NPCs seems to be, Kavode's statement makes sense and it never occured to me, and if that combined with the fact that we'll get more companions down the road who aren't quite as "special" then it could be good. (this mind you raises the concern of party size. even in BG2 with it's 6 man party size I had some companions who didn't get much attention) we'll see of course, this is early access and Larian would benifit from our imput even if it's to point out some holes in their writing.