One point to note about Ryan Tannehill. As a young strong armed QB he is well trained on throwing hard-to-intercept bullets. Unfortunately they are also hard to catch and require good receivers, which we now have IMHO.
Part of his difficulty with the long ball is that those bullets give far less time for the receiver to adjust to an over-the-shoulder ball. Regardless of whether the WR ran a sloppy route, was held up by the DB, or Tannehill was off on the throw, the WR gets very little chance to adjust. This can be exasperating for a WR, and I believe is part of the reason his old WR's were so frustrated with him.
Tannehill NEEDS to develop some touch throws for his aresenal. Screen passes, short dumps over long armed DL like Watt, and long bombs all require substantially more arc and less velocity. It's a different kind of throw.
Up until this point, Tannehill hasn't practiced those enough to gain the proper muscle memory or become skilled at gaging the deep ball. Personally, it surprises me, because he is smart and hard working.
It's like a medieval warrior going into battle with a long sword and a shield ... but no knife for when he fighting gets too close quartered for a sword.
Hopefully the coaches know this and are having him train both types of throws. But so far, Tannehill is very erratic on those "touch" throws.
One of the hardest plays for me to watch is our botched RB screen. We screw this up all the time. Miller has terrible hands, so when the ball gets to him he drops it a lot. Miller runs bad routes and never seems to run that route the same way twice despite the route being like 7 yards.
Tannehill's throws look like he practiced it twice ... ever. Some throws are too short, some too far in front, and every one looks aimed rather than confidently tossed. The whole thing looks forced, unnatural and unpracticed. With competent RB screen and flare routes, we become better at slowing down the pass rush.
I think Ajayi can do that. Now, fingers crossed, Tannehill can develop some touch and we can add that as a staple of our offense.