I'm not going to take your question seriously, 'cause it would never happen...
That said, I was a big Stallions fan in the 80's. Seen as many of the current Stallions games as I could afford the last two years. I was VERY skeptical of Skip Holtz when they first hired him but I have been nothing but impressed so far. That first draft he did was really good and the way they drafted and latter managed the QBs was just about perfect. It is pretty tough to draft two QBs that you are comfortable can win games and he knocked it out of the park with J'Mar Smith and Alex McGough.
I don't know if you can say a successful USFL coach would make a successful NFL coach as they are two different species, but I've been very pleasantly surprised watching him run the Stallions. They play hard every game, don't make a ton of silly mistakes and he doesn't waste a lot of time trying to sell the team to the fans. He sells the team to the players and lets the results on the field speak for itself.