The thing is no one is using the same criterias when deciding if a player is "a good skater": agility, top speed, edges, first steps, stability, etc.
All I know is that if both Chester AND Estimated Prophet deem someone (other then McDavid / Makar / Hugues / McKinnon) a good skater, we should draft / trade for him asap
Some of the warts those prospects have we're not aware. It was recently mentionned that Mailloux kept arriving late/last-minute so his Laval teammates cut his skate laces and he got the message (and that was a bigger hurdle for his pro career then his skating).
IMO his main challenge remains defensive play and risk-evaluation (cuting down on the risky / lowish reward plays). He needs a lot of reps and the ability/mindset to learn, his skating won't carry him to the NHL but I doubt it's the make/break factor.