Oh come on the companions in BG were super uneven. You had very good ones, very good but shallow ones, underdeveloped ones and boring and lame ones.
Yeah, I'm not saying they were even. But most were good. I'd say underdeveloped and boring ones were more of an exception that a rule, at least in BG2. Cernd, Nalia and maybe Valygar? In BG1 pretty much all were underdeveloped, some were better than others, but I wouldn't say any one was entirely bland (if only because the cardboard had to be made quite over-the-top and memorable to seem alive).
And, going back a bit in the discussion, that's why I think it's better to have more and "uneven" on purpose (in terms of depth). So you have "fun" ("good but shallow" as you said) alternatives for the "deep", but potentially disliked (as everyone's taste is different and the choice is limited) origins. And so you don't need to resort to mercenaries.
