Osweiler has never been better than he showed. He was hand selected to start in an established offense with some talent by an established coach. He was also traded because his contract was a talisman of incompetence. Chicago might have had the same experience next offseason, but they drafted a savior behind him.
Kaeppernick was in year 1 of non-NFL Chip Kelly's regime with a dearth of talent. And he out played him. Passer rating or DVOA or ESPN QB index or eyeballs, he was better. In the pocket, he was better. Outside the pocket, forget it.
Market failure. Someone above wrote he will be brought in by someone who loses the established starter. This is probably correct by now. Because he is the only body out there who could actually help you win a game. Its just that no one wants to admit their backup is just window dressing.
Does he have touch? No. He lacks several throws he needs in a traditional offense. You will need to adjust the offense. But that is almost always better than fitting square pegs into round holes. The talent will show through if you let it. Your scheme is not so precious, nor the only way to skin that cat, that it makes it worthwhile to hold on to Hackenburg, McCown or Davis.
Even Matt Flynn struggled to go .500 while keeping M3's offense intact.
Teams cannot afford to get cute with a starting QB. They are happy to get cute in the offseason with a backup QB.