I wanted the Bills to draft Wilson, but having watched him for a while now, I have my doubts about his long-term prospects. When they take his runs away from him (and they will, either through defensive adjustments or physical pounding that slows him down), he'll have to depend strictly on his arm, and I'm not convinced he's a Brees-level thrower and field general. Time will tell, but it's easy to see him having his best seasons in the first three years of his career and then declining.
The problem this year is knowing when to take the plunge on a QB. Nix should have done it sometime in the past two years (I wanted him to trade up three spots and take Tannehill ahead of the Dolphins, in part because I thought he was worth it and in part because it would have been fun to stick it to the Dolphins). I wanted Wilson two rounds later. I wanted SOMEONE the year before. But that's history, and now Nix is stuck with having to make a move. I don't think he'll trade up for Smith, and it may very well be the case other positions offer MUCH better value than a QB at 8. Best choice from my point of view is trade out of 8 down to 12 or 15 or 20, wherever you're very confident that a QB you like is still there. That way you pick up a second pick in the second round, which leaves you in position to get a good QB prospect and still get valuable guys at WR and LB.
Very tough to know how to play it. We thought Nix wanted a QB in the second round in 2011, but there was an unexpected run that left him with no good choices (although in retrospect Kaepernick was a good choice). His problem now, as you say, is that he can't afford to wait long this time.