My view hasn't differed for some time.
Good player.
Great athlete.
Capable of some great individual moments (Man City/Newcastle/Norwich).
Doesn't possess the mentality to be integral part of any top club.
That last point based on his hesitancy on the ball and he didn't "boss" enough games for Everton, his bottle went in every single Merseyside derby.
But this is not unique to him, I always thought there was a player in there but as has been said think he was badly unprofessional and never really improved.