On writing Nix off... I think it really comes down to skill sets. I know hockey much more than I'll ever know football, but skill sets are incredibly important in all sports... arguably QB in the NFL tops the whole list. If a player doesn't have the requisite skills, no amount of hope, coaching, experience, time, etc will matter. I keep coming back to it... but the NewJost situations. It was abundantly clear before these players hit the NHL that they didn't have the requisite skill sets needed to succeed as 2nd line centers. They should have been written off from those roles very early, and moved into roles that were more fitting for their skills. If the Avs has moved Newhook to wing early, and developed him there, he might have had a better shot of sticking here. Jost was probably too far gone, but he would have had a better shot of carving out a lesser role if he wasn't forced into roles he was unfit for.
I've watched a lot of football, but I'm far from an expert. In my eyes, Nix does not look to have the skill set of a good NFL QB. He's a bad combination of a below average arm and gunslinger/risk taker. You can deal with one or the other, but both in the NFL rarely works out. To me, Nix looks like a guy who bounces around the NFL as a backup who gets 1-3 starts a year.