The bad news is ANY NFL QB should be good when given time. The question is, HOW good? The good news is, against Dallas, the anti-Tannehill crowd has almost nothing to cite as evidence, except reverting to previous years when Gase wasn't here and the OL sucked. FWIW, I watched a few games the last few days. ALL QBs made bad reads/throws. ALL QBs 'didn't see' open receivers. ALL QBs stared down an occasional receiver. How will Tannehill do THIS year? I don't know, but without a baseline, I can make Brady look VERY bad.
That is something people miss, they see the highlights, or redzone, but rarely watch the entire game, at least with the same attention they give the Phins.