I tend to agree. MacKinnon is playing in Denver in relative obscurity. To be honest I also haven't followed him closely.
I saw him this Spring in Cologne for all games (they played the group games in Paris tho). He was an absolute force. Tied for 2nd in the tournament with 15P in 10G (Mark Scheifele had 8P in 10G). My point? > He looks really good with a supporting cast.
MacKinnon is a good player, with perhaps questionable leadership (he's young, this isn't an attack), playing in a bad situation. Like many of the pre-McDavid Oilers, this is a player struggling with responsibility in a difficult situation. It does not, necessarily, make him less a player than his (slightly older) contemporaries who are playing well in good situations.
I expect him (and RNH for that matter) to re-establish themselves as the elite talent they are, once the stink of losing dissipates and they re-establish their confidence.