In 60 hours of gameplay, I've lost a companion on the Whisper Tree to the drow wizard's thunderwave only once. On the other hand, I've taken out dozens of enemies by throwing them into chasms or causing significant falling damage. It all comes down to good positioning, and honestly, I haven't noticed this AI doing everything it can to push your companions. Naturally, in encounters near adjacent chasms, it's a given that you should be the first to capitalize on it, just as it's logical in an actual fight.
