As far as the Mayer vs Schultz comps go. I agree athleticism can be quite important. The fact that Mayer is not much more athletic than Schultz can be a cause for concern. I think it's important to compare their college success on the field as well though.
Schultz: 33 GP (red-shirted as a freshman), 55 REC, 555 YDS, 10.1 AVG, 5 TDs
Mayer: 36 GP (started over NFL TEs Tommy Tremble and Brock Wright as a true freshman), 180 REC, 2099 YDS, 11.7 AVG, 18 TDs
Not to mention Mayer is a stronger blocker now than Schultz was entering his draft. I feel like a lot of people on here see Mayer/Kinkaid as another Schultz, when in reality their ceilings are much higher because they're far more advanced at this stage of their development process than someone like Schultz ever was. Not to say they're a lock to be better than him, he's a solid starting TE, but there's certainly more to work with early on.