The NFL just doesn't like small Qb's. There are exceptions, but they frequently seem to be right about that. It's not about the throwing so much as it seems to be about a lessened ability to take a hit consistently. Honestly, we've seen that a bit with Romo. I think the Skins saw that with RG3. Size isn't a way to avoid all injuries but it does seem to help.
Maybe Adams goes up to Canada and learns some and shows some skills and comes back down like Moon or Flutie. Maybe he carves out a career for himself up there. Maybe he never learns how to improve his game enough to stick up there. Who knows.