I know you're joking, but right now, unfortunately, I don't see Hemsky even in the same league as Kovalchuk. Hemsky doesn't have the ability to grab hold of a game the same way that Kovy can, to take it and make it his own. Few players have that ability. I'd have to say too, that Heatley doesn't belong on any list right now - it remains to be seen what long-term effect his troubles this summer will have.
I think, actually, that I'd rate Comrie above Hemsky right now, with the caveat that I'm cheating and using past performance as a guide, where I rejected doing so for Heatley above.
To grab a game, I think a player needs to be able to either be absolutely dominant physically, or to score the game-breaking goals - the other team just scored, you're down 3-2 with five minutes left, and you go out and pot a pair. Hemsky can't (yet?) do that - he just plain doesn't score goals. Comrie does. The best players have both characteristics - like Messier in his prime, Lindros when he's on his game, and even Forsberg. Forsberg doesn't have the big hits or the fights, but when he's cruising, he absolutely can not be knocked down or off the puck. If you do knock him down, he gets right back up again, picks your pocket, and gets a scoring chance.
Hemsky's gonna be very good for sure, he's proven he's a good playmaker, but it remains to be seen yet if he'll be able to jump his play to join the superstars.
(Edit: back on topic, I'd put Kovy at 10 - he's not perfect, but he's MORE perfect than the others, and MC at about 8. Hemsky at 7. He could be a 9 or 9.5 if he'd just SCORE.)
i put Hemsky's ceiling above Comries right now. Comrie seems to be a guy who has to work his a$$ off every night to have a good game, Hemsky seems to have that natural ability that even when hes not on top of things, he still makes the plays look effortless and gets the points.