While I agree that humans should probably 'be the norm' to provide a baseline for the setting and give context for the other various races to be unique against...there should also be a priority in making sure at least the most basic races should be covered. That is to say, in a game with 12-15 party members, sure. Make 6-8 of them human. But BG seems to have a pretty small number of party members compared to the prior entries. 'mostly humans' doesn't really cut it as well (and shadowheart & asterion's elvenness isn't really a big part of their culture or personality anyways, so what's the point)
We need more party members period is what we need. No more humans though, please. Gimmie both flavors of drow, a dwarf, a gnome, a halfling. maybe a half orc or another elf, then we can look at humans again for options. And if we do, for the love of Ao, not another Baldurian. The Realms is huge, gimmie someone from Amn or Cormyr or Mulhorand or *anywhere* other than Baldur's Gate.
Well if the non-human party members don't feel non-human that's just further proof of my earlier point. The unusual became so usual that it no longer has a chracter of it's own. Even Lae'zel just feels like an exotic tourist with a small nose, even though githyanki are phisiologically supposed to be quite different from humans, they even reproduve via laying eggs. So why isn't she more lizardlike or even birdlike? Her personality is basically just violence, but she isn't particularly feral (I mean I like her, but she could just be a human and I would still like her, her race has nothing to do with it, it's just a rather minor cosmetic detail.)
I think that race should matter a lot more then it currently does, right now it just seems purely cosmetic from a roleplay perspective (from a powergaming perspective the differences are still meaningful).
That being said I do agree with you that we need a dwarf and a halfling companion, a half-orc would be nice as well. But for every nonhuman companion, we should get 2 human companions.
