I agree but one thing to keep in mind is that even though he's small he still does play big. He's of the firy type, loves to hit, isn't afraid to fight as well.
Of course that can be a concern as well with teams questioning his durability but my point is that it doesn't really matter if he's 5'10 or 5'11. He's gonna mix it up regardless. Just a highly competitive kid.
I actually like his skating. Very clean technique. He's not the fastest or most explosive skater but he's very mobile. Seems to have a lot of energy as well. Played heavy minutes at times but hardly ever looked physically tired.
His skating is ... OK. It's the thing where it's good by WHL standards but in the NHL virtually everyone was an elite skater at lower levels. It's not terrible or a liability but it won't be a plus skill moving up levels. He'll be an average skater if he makes it.
He's had one fight in the last 2 years and he was basically jumped by the other guy so I wouldn't list that in his skill set. He's competitive and plays an involved game, absolutely.
5'10 or 5'11 does matter. It might not be singularly make-or-break but it does matter.
I like the player and like his compete but I can also see where NHL teams simply don't value smallish middle-6 winger types, especially when they don't have plus skating. It's easy to find Erik Haulas or Pius Suters for cheap to fill out your roster.
If I was simply trying to draft the player who will play the most NHL games, I'd take Marques over a guy like Carson Wetsch because Marques is a better player now and has a higher floor. But if I was an NHL GM trying to draft assets that fill needs and have value, I'd take Wetsch over Marques because if Wetsch hits he's a much more premium asset.