Just to return to the original question, I think the general consensus is that Reinhart isn't the best player on the team. That's not at all a knock on Reinhart - given his hilarious post-goal WTF reaction to some of Barkov's incredible assists, I think he'd be the first to agree...
There was a really interesting episode on the Hockey PDOcast on Reinhart's amazing season last year. From what I remember, along with just how intelligent he is, the hosts talked about how Reinhart is complimentary player in the most elite sense of the word: he's the type of star player that has all the elements of greatness but, unlike other star players, he requires the right type of chemistry to get there. And happily for both him and the Panthers, that chemistry just clicked with Barkov and the team last year.
That stuck in my mind because the hosts went on to talk about the tragedy of players who have that same potential for greatness but are not put in situations to realise it, and then start to believe that they are less than they are. Which made me think about just how random and cruel this sport can be. I know that's obvious, but the tragedy of wasted potential struck me more after listening to this episode.
Anyway, here's a link if people are interested: