At this point I think Tim is a victim of his own brand. Nobody wants to deal with the circus, and I don't blame them. Tim is easily in the backup QB tier to even the pessimistic of coaches, but why bother with the circus?
However I do think Tim can easily be an above average QB, if not Pro Bowl caliber given the right situation.
What Tim needs is simple, an innovative offense. Some pistol, some spread, some zone read, lots of shotgun, etc.
This type of offense is taking the league by storm. If Tim came out this year he would be a consensus top 10 pick. He came out when the consensus was that you have to be "pro style" even though many teams were going to the shot gun with many spread principles.
Now look at the coaches that are having major success using innovative offenses. They are either college coaches, innovative offensive minds, or extremely established coaches. What Tim does NOT need is some stubborn NFL DC turned head coach that only understands under center pro style. Of course that's what he got with Ryan and Fox. Colin K and Russel W both would have struggled with Fox and Ryan as well.