Why all the red dots!!
Back on topic: I feel Muzza surely has the talent to be able to win one (or even more) slam, but if anything, he's not there yet. Apart from the points already mentioned, he doesn't come across as mentally stable enough. But he's still young - and remember, Federer was regarded as a 'total headcase' in his early days, and see what's become of him. Not too bad I'd say.
So we just can't tell.
Let's see if he manages to take Marseille this week first, before starting any speculation on winning slams...