Lae'zel is a typical gith and is reacting accordingly. I never have much approval with her or Astarion, but that's ok. Those two are clearly meant for evil playthroughs and I prefer playing good. They should be absolutely disgusted by me.
I usually get approval with Lae'zel, if I show strength or act against the tadpole, so being mean to that cambion (forgot his name) gives some approval or promising Nettie to take the poison, if you notice a change in your condition.
Since companions don't leave for approval reasons just yet (I know that companions can leave because of certain decisions though), I don't see a problem. And with full game release, we probably have enough companions to choose the ones, that fit our playstyle the best.
