It's a difficult one - I couldn't stand him for around 7 years, he turns heel on Mysterio and I still hated him. Then he becomes the guy who just didn't give a crap anymore and just had fun doing what he was doing... and he was brilliant.
I have a sneaking suspicion that he'll come back, and be nowhere near as good as he was when he left. His heel character worked because he was leaving, and just enjoyed what he was doing. If he knows he's going on the road full-time again, he'll be sulking about not getting into MMA or being a Hollywood star and having to come back to WWE...
I just can't see him being as good as he was when he left.