The measure of McDavid's contract value is not against other top players in the league. It is in consideration of being the economic engine for the franchise value of the Oilers (Forbes #7 among cartel members at $2.4 Billion) and in setting the league's annual revenue record for his owner. For perspective, in 2012/13, the franchise valuation was $400 million. I don't think it's out of the realm of possibility that post career McDavid might receive a stake in the franchise.
As for the player who will likely ultimately finish his career as a top 3-5 all time, I don't tend to necessarily look at perceived deficiencies in his game but moreso the bigger picture. The league has game planned to stop him and the lethal power play and we see some of the effects with aggressive neutral zone defending to contest his zone entry speed and, always facing opponent top competition, layered in-zone defending to flood the warp speed cheat code and force other Oilers to beat them. Stack the house and force McDavid to skate perimeter distance using time and energy to assess and look for vulnerability. His regular line mates have also regressed from peak career season, Hyman this past season's goal scoring dropping by 27 and Nuge a steady drop from 104 points to 67 and last year's 49 points.
I agree with others suggesting load management might help especially as extra duty to God and Country call for more with 4 Nations and next year's Olympic. Time for ownership and management to ask not what (more) your Connor can do for you but what you can do your Connor. They're on the clock to build around this rare gift and likely some fresh coaching to re-energize a somewhat stale power play.