I found Astarion much more unlikable, because in the short time I allowed him to stay in the party he was always making snide remarks or popping up "Astarion disapproves" every time I wasn't a dick to someone. Lae'zel was a bit grating at first, but once she settled into the group (and I told her I didn't want to have sex with her) she made a good companion. I don't think she and my character ever became true friends, but I think there was a good mutual respect between them. And her exclamations always made me smile.
It's normal for compulsory video game companions to be designed to be likable, but none of the companions are compulsory and it's nice to see some variation in personality. According to the BG3 art book, they softened Lae'zel's appearance to look more human and make her more appealing. I always interpreted anything inappropriate in her behaviour to her youth (the art book suggests she hasn't quite reached maturity), unfamiliarity with culture, and her upbringing.
