This is a question, and not a comment. Not living in South Florida, I have only had the chance to watch Tanny a handful of times. When I have, I've seen consistent inaccuracy with throws, especially the deep ball (a shame when Wallace runs past the defender), and no indication that he's figured out the mental part of the game. So, what is it about Tannehill that would cause anyone to believe that he might be better in the future? In what way is he better than Matt Moore?
Walt, I'm going to try to give you an honest answer. I'll probably get flamed for it, but I'm going to try anyway.
You said that Tannehill has given "no indication that he's figured out the mental part of the game". I would disagree. When the coaches and analysts talk about Tannehill, most of them agree that he's not making completely boneheaded decisions with the football. For the most part, he's not throwing into coverages he shouldn't. A good example is the interception he threw against the Patriots when he tried to hit Wallace late on the deep post over the middle. Tannehill came off his primary and saw Wallace clearly, but he never set his feet correctly and instead of leading Wallace on the throw, the ball drifted on him and was picked. I see a quarterback who has the mental capacity to grasp the offense and knows decisively where he wants to go with the ball on his 2nd and even 3rd reads.
Here is where I agree with your assessment. Tannehill's accuracy is not where it should be at this point. There was mention this offseason that Lazor was working with him to improve his foot placement, and I have a feeling this work has continued into the regular season. Maybe it's because he hasn't had as many reps as other top quarterbacks, but there is something in his footwork that makes him inconsistent. On shorter throws, he often gets away with it because there is more margin for error. On the deep throws, his margin for error is smaller and this is why he misses the connection. Tannehill also needs to improve his movement in the pocket. Right now, he's just not very good at sliding around and resetting his feet. Contrary to popular belief, pocket movement can be learned.
I still have hope for this reason. Mechanically, there is nothing wrong with Tannehill. He has a gun. He has no hitch. Among current NFL starters, he's also probably in the top 5 in terms of athleticism. If he gets his feet right, I think you will see his accuracy improve dramatically. I think Tannehill has the same problem that I have in my golf swing. He can see what he's doing wrong on film, but he can't feel it consistently under fire. If he can ingrain the good feeling so it becomes second nature, he will likely have the problem corrected long-term. That said...time is running out. It better be clicking by mid-season.