I don't think McDavid should take more than $11M AAV for 8 years. If he takes more, he reduces his chance at winning a Cup. Money won't be an issue and he's going to get his share with endorsements. Hockey is the ultimate team sport (like soccer). There are individual stars but in a Salary Cap league, Stars need to be cautious with how much they take in salary if they want to win several Cups.
Crosby at $8.7M is one example. Just imagine Crosby at $12M over the last few years. Would they of had room to go get Kessel?
McDavid at $13.25M likely means Drai is traded or both RNH & Lucic are unloaded with minimal salary coming back. The 2019-2020 season is the biggest problem. McDavid, Drai, Nurse, Strome, Talbot, Maroon, Puljujarvi with new contracts. That's about $40-$45M in cap hit right there on top of the $33M already committed to 7 players. So you have 14 players signed with very little money (maybe $3M +/-) to sign the 9 players you need to reach the 23 man roster.
Oilers better draft well so they have multiple young players on ELC. There will be no room to sign free agents.