I think fast and accurate brain is still much more important. Sure, you can’t have really bad skating at the NHL level. But quite average skating can still be enough to be even a true star player, if you have exceptional hockey IQ. On the other hand if you have only average hockey IQ and excellent skating skills, you will never be a true star player in the NHL.
I don’t also think that Dumais isn’t even just an average skater. To me he looks more like a bit above the average NHL level with it. Sure his straight line speed isn’t anything special, but he has pretty good agility and even his acceleration is good enough. His skating as it is is good enough to be succesful with the stop and go-play that NHL is very much about.
But sure, as Dumais isn’t by any means an exceptional skater at the NHL level, he will not be a game breaker without having some high IQ players playing in the same line with him. But if he gets to play with one or even two of those kind of players in the same line, then its’s going to be something special. And Columbus does have some pretty special high hockey IQ players in Gaudreau, Laine, Johnson and Voracek, so they might be able to try something special, maybe even next season?