How this new Bills owner can keep any of the people in charge of the football operations I would find baffling at this point. They have totally screwed up the last 2 drafts. You draft EJ Manuel in Rd 1...then just bench him after a 2-2 start this year. All young QB's go through rough patches, you ride it out and stick with them. Miami did it with Tannehill for a few years and look at him now, no he isn't a world beater or an elite QB but he is pretty darn good and its beginning to pay off. Jax is doing it with Bortles now. The Raiders with Carr currently. Gotta let the kid take his lumps to see if he is "the guy"...benching him just prolongs the inevitable of finding out whether he can play or not. Then they gave up a future first round pick for Watkins in a draft deep with WR's. Which will hurt them going into next offseason. Brandon/Whaley/Marrone have made some bad decisions the past 2 years and have messed up 2 drafts and are getting no results from their early round picks.
As a Miami fan, I was against the Tannehill draft selection. At the time, he seemed like the third best QB in a draft with two "sure things" at QB in Luck / RGIII [and obviously, Griffin's status is still uncertain]. I thought it was a reach at the time, taken by a team desperate for a starting QB.
Instead, he's looked quite capable from the beginning. He lacked weapons his first year, but despite the natural growing pains / rough patches that you describe, in the main he accorded himself well. Started out great last year [again, without a great running game or tons of receiving talent], but the season got derailed by the OL issues / scandal around mid-season, and he got sacked a TON over the second half of the year. Amazingly, the team somehow rallied and nearly made the playoffs... only to completely sh-t the bed the last two games.
This year, with an upgraded receiving corps and an improved OL, to say nothing of a new offensive concept, Tannehill looks great. I'm not sure that he's elite in the sense that Rogers, Brees, Brady, are elite--but there is no doubt in my mind that he can be a top 10 QB in this league. Especially as they continue to add pieces of the puzzle around what is shaping up to be a good offense.
Sky's the limit from here on out with Tannehill. And I understand the Bills fans' pain all too well--because post-Marino, we went through about 23 ineffectual starting QBs, always trying to catch lightning in a bottle with some washed up veteran. It is a much different situation when you go into a season or a draft knowing that your QB situation is solid, and that you can expect above average play instead of desperately turning over every rock in search of a serviceable alternative.