When I think "Great skaters" I think of guys who used it in the context of the game. I like the OP's list, it is unique, I will admit I was surprised to see Mario there but do agree with his assessment that he was big but smooth.
You could pick Rico Fata and he could make any sort of list just based on speed. But he didn't do it well within the context of the game. His head wasn't there, the puck got caught up in his feet a lot. If I am picking players I want their speed to be a big part of their game and what made them great. So..................
Bobby Orr - Need we say more?
Gilbert Perreault - Just elegant and beautiful, made you glad you watched hockey
Pavel Bure - Choppy skating stride but it didn't matter the way he blew by you
Connor McDavid - Like Bure when he had the puck I don't know if anyone can skate faster at full flight
Paul Coffey - Would glide backwards than others skated forwards and it didn't even look like he was trying
Sergei Fedorov - Think Coffey's style of skating but as a forward. Might be one on this list who I think could have utilized it just a bit better
Mike Gartner - Choppy, but man could he fly. Maybe it wasn't elegant like Perreault or smooth but you ever seen him in full flight down the right wing?
Guy Lafleur - Fast, smooth, a treat to watch, long mane of hair blowing behind him and effortless
Yvan Cournoyer - Watch his goal in Game 2 of the 1972 Canada/Russia series. It is the epitome of a player skating around a pylon
Bobby Hull - There is a reason they called him the Golden Jet
Honourable mention: I wish there was more footage we had of Syl Apps. He could easily be on here and I won't ignore Rocket Richard either on this sort of list.