I am still a Tannehill supporter and he has shown that he has the tools to succeed. And I think he will.
With that said, he was expected to be the most improved from last season too... he improved, but he definitely didn't take the HUGE (almost unrealistic?) jump expected of him. If he improves at the consistency of last season he could be an above average QB and lead us to a winning record.
IF Miami had the O-line and RB consistency of 2012, maybe the big leap would have happened, but they took a huge nosedive on both those positions....It's amazing enough that Tannehill had the year he did, with all that was happening around him.