Lae'zel is fine, for what and who she is. And you're never going to be friends with all your companions at the same time in the same playthrough - that's part of the game.
There is nuance, or at least the beginnings of it, and I believe once we are able to go to the Gith Creche her story will really start to unfold. (And her mental state will probably start to unravel!)
