I like Lae'zel as she is (although she will probably not be in my party) and would oppose a change of personality. I don't see inconsistencies with her as character which aren't explainable by her background and the situation she is in.
She is part of an arrogant warrior race/caste and sees us as companions as inferior beings, like worms. So she acts harsh and as if only she can decide what to do. But she is insecure (and perhaps intelligent) enough to realize, at least sub-consciously, that that's partly a fake and she is not so superior and independent as she wants to be and braggs to be. When she tries to kill you in one scene and you enter her mind, you notice her doubts she has about herself. Insecure people often need to overcompensate and be radical, as you find a lot in our world. Lae'zel's harshness and despise and at the same time her reluctance to leave the party and do her own things are not contradictionnary, having that in mind.
