i dont think its that he is lost without Smith, but that he benefits when he is the centre of attention, allowed to just go and do his thing, no strings, no responsibilities, where he can just go out and fully express himself, and the play revolves around him.
Unfortunately, he was only allowed to do this at Villa, not with England, and certainly not with Man City.
Its amazing how average he looks when Man City dont "play to his strengths", he really doesnt suit their style of play...at all.