These are great players , but I think Sam Reinhart is more clutch than Mckinnon and Mcdavid . Sam Reinhart will get you're team Stanley Cups and Sam Reinhart will win Con Smythes . I know this thread is about Mckinnon and Mcdavid but I had to throw Sam Reinhart into the equation .
McDaxid will be better than MacKinnon. Just like how Tavares was supposed to be better than Stamkos, Larrson was going to better than Hall/Seguin, Yakupov better than RNH, Mackinnon better than Yakupov, etc.
No professional scout thought that Yakupov would be better than RNH, almost all are thinking that Mackinnon is better than Yakupov and C Mcdavid is more talented than neither one of them and is pretty close to RNH.
Also as of huge fan of Connor and RNH i must say that from past 3 years there has only been one guy who is offensively as talented than these two are and that guy is Teravainen. They all have same kinda playing style and they finesse as hell with them passes.
Big MacKinnon fan/proponent and Halifax resident here, but I think the ceiling has to be a bit higher for a 15 year old sharing the same world stage as 17-19 year olds due to his "exceptional status" - especially when you also consider his production to date in the OHL.