On the surface, bringing Petofi back would have been excellent. As others have mentioned, it would have been great to see him interact with the family and his reappearnce would have given Quentin something to do (why they didn't do anything with him during the present time storyline, I dunno).
Then again, if the right people weren't writing it, the whole thing would end up being the Dream Curse II: Petofi Style or the characters spend the entire storyline doing the mind/body switch, which really got annoying after awhile **shudder**
So I'm torn about it