I don't necessarily think Wilmer is a bad skater for his size. Zuccarello is similar, he's not a bad skater but hes not really a burner. He's got some speed but really it's his elusiveness and creativity. Whereas someone like Gaudreau, his skating compliments his offensive ability. Really the problem with Wilmer is his strength/weight.
Zuccarello isn't the fastest player but he plays at 180 LBs. DeBrincat and Krug I've seen varying numbers. They're jacked though. St Louis played at 180... he had tree trunks for legs. Nothing wrong with that size player in the league, but you need to be strong and have some weight. From what I've seen Wilmer is still in the 150s... maybe if his skating or puck abilities were outrageous that would mask some of the size issues. But that's why the college route is good for him, the skill isn't the issue, he needs to get heavier/stronger. You'll notice it often against bigger players he gets knocked off the puck way too easily. A lot of those smaller guys in the league, you can't just flick them and they lose the puck, that's kinda where Wilmer is at right now. He really needs to add another 20 pounds. And this is coming from someone that thinks he was easily worth a draft selection as a project