I think it’s self-evident that it was a mistake, given their record, but to me, the mistake was getting him without the intention of really using him. If he could lead the Broncos from a disaster season to the playoffs, there has to be at least one team in the league that would be willing to give him a legitimate shot, from training camp on.
A lot of that success in Denver was the defense shaving 15 points off their average allowed. He’s really not a good QB. His throwing motion is slow, his throws are inaccurate, he can’t read defenses. He runs well and he’s a hard gamer, should be an RB with the occasional gadget play. Somebody might still give him a shot, there’s plenty of teams with even worse QBs, but don’t expect much.