In addition to how long it takes to get Imoen's thieving skills back due to low amounts of XP in BG1, the timing is just awful. In the later stages of the game you need to be able to detect traps. Okay, others can do it, if you know exactly where the traps are, but if not, that is a pain in the neck. And if you for instance dual her at level 7, she won't get the thieving skills back until pretty much the credits roll. I did it once, but never again.