I don't think, he needs a rewrite, he needs more content. People will always go for the flashy characters and not the morally good. Maybe give some examples of what you would like Wyll to do. 'Re-write everything' is not helpful. That is, what I would write for Halsin (better write him out), but that is not really helping. I'm not vibing with Halsin, so I have no idea, what to do with him, maybe it is the same with you and Wyll?
I am not sure if it's the flashy that is important, it's more the relatable, in my opinion. Whether it is because you know the feeling yourself or can just empathise with the problem without necessarily having made the same experiences. Though, maybe it's just me. In Wyll's case, I am not even really sure what his problem is. To me it seems to be more an external one, than some internal battle he has to overcome. In Halsin's case I would say, that he lacks stuff to do as well in Act3 but I kind of get it. He spend the last 100 years trying to fix a problem he feels responsible for, which has both claimed a good friend of his and the inspiration for becoming a druid. In Act 3 he is basically looking for a new purpose and finds it in the end, but he unfortunately resolves it off screen, which is not very helpful. (I really thought he or Jaheira would have some interaction with that little tree.)
