My gripe with Kane is that he's a law of averages kind of striker.
He's got great shooting ability and huge confidence (an underrated trait), so his tactic is to shoot whenever he can.
Because when you have that ability and confidence, a lot of your shots will be on target. And with his ability a lot of them will be unstoppable and go in.
So naturally against the weaker sides he scores a load because he has a million chances to shoot and he takes them happily.
But when Tottenham, or more likely, England, come up against a side where he won't get many shooting chances then he'll be nullified.
He's not quite technically skilled enough to pull the proverbial rabbit out of the hat like Sergio can (United away 2013 best example amonsgt many) nor does he have the pure poaching abilities of players like Hernandez who can snatch a goal.
He's a bloody good striker, but not world class for me. The only way I can see an argument around the idea is if you consider his consistency a valid reason to call him world class (In my opinion it helps but not on its own)