Funny that Elway never got a ring until Shanahan came in, established a solid OL and turned late round picks into 1000 yard rushers. In fact, Elway made significant improvement under Shanahan and I would expect he would do well with Tannehill.Coughlin is 70 with a losing record the past 4 years, Shanahan built his name off Elway, although I like what he can possibly do for tannehill and how much he believes in him. And the AFC East isn't that tough, Brady is nearing 40 and soon to retire, the Jets are a one year wonder the size of the sparano led 2008 Dolphins, and the Bills are nasty but Rex Ryan is an underachiever.
As for the AFC East not being that tough it is arguably the best division in the AFC. Not sure what you're basing your assumptions on but Brady isn't slowing down and if the Jets get a QB watch out.