I'd also be willing to try one of Kap, RG3, or Manziel for a year to see how well they could play in chips system since I don't think he is going anywhere. The last thing you want to do is give an average to below average QB a medium or long term contract. Then you are stuck with a bum at QB and stuck in the middle of the draft instead of picking toward the top.
That's how I look at it. Kap and RG3 are guaranteed to be jettisoned by their teams one way or another (cut or traded). Manziel has played well in his limited opportunity this season, and I am not sure if the Browns are going to cut ties if he plays well to end the year. All three of them should be considered at least as potential options. Bradford is a good QB. Don't get me wrong. If they bring him back I won't be disappointed (though I wouldn't want a long-term deal because of the injury potential). If they let him walk and go with an open competition, it could pay dividends. Chip's offense isn't going to be what we want it to be if he doesn't have the QB to run it the way it should be run. We've seen guys have success who can't run the ball, but there is just so much more potential having a true threat for the read option, or even just to scramble if need be. Foles was not a runner. Bradord is better on his feet than Foles, but he's nothing special. Vick was a good runner but his throwing wasn't great at that point, and IIRC the knock against him was inability to read the blitzes and effectively operate the hurry up offense.
Is RG3, Kap, or Manziel the answer? No idea. What we do know is that Bradford is kind of in the same spot as Foles. Solid QB, but nothing great and not necessarily the best fit for Chip's system. Are we winning a SB with Bradford in the next five years? I'd bet against it. Are we winning one with RG3, Kap, or Manziel? I'd probably bet against that too, but at least there you have the hope that one of those guys (or I suppose a rookie or other potential candidate I haven't considered) can really execute this offense with the ability to move around more.
I wanted to roll the dice on Mariota and give up everything to get him. I wouldn't do that for one of these three options, but I would roll the dice on them in the sense that giving them a chance is rolling the dice.