Got to agree with this. If you're going to compare Tannehill you need to compare him to players like Ponder, Locker, Luck, RGIII, Weeden, etc (this would be the high potential tier) until he advances to the next tier of quarterbacks. You don't compare him to busts and future career backups.
And I don't fault nyjunc for having all this hope on Sanchez. When you invest a high draft pick on a quarterback you want that guy to succeed badly. It sets you back years if he doesn't succeed, which is what you're looking at now. He is still hanging on hope but eventually he will give up on him too. They need to draft another quarterback, and I'm sure Rex is thinking it, he can not continue on with Sanchez or risk getting fired.