The scheme and the play call dictate the throw for the most part.And this is where you are wrong - I admit the fact that Tannehill has a better team around him and a great RB.
What you guys don't see is that Tannehill's approach to the position very much compliments those things too .... while Watson's approach is more like Mariota's in looking for big plays instead of just moving the sticks. That's why that team took off when they made the QB change.
Mariota was / is much more dynamic than Tannehill , much like Watson he can escape pressure and is at his best scrambling around .... but in the NFL you simply aren't going to make enough of those kind of plays to win consistently , especially against the better teams.
That's why Mike Tomlin said Tannehil is a game manager. And he meant for it to be a compliment, noting that Tannehill is playing very well.
(He's been a little lucky on the Int department as I had noted in the game thread - at least 2 of his throws this year should have been Int, with a possibilty of 3-4 more by my count.)
The Titans fans had ackowledged those two "should have beens"; they were not my imagination.