You are forgetting 2 important things that are not Oline Dependent. He has horrible issues catching with his hands and he has 0/zero/none/zilch/No Heart (NO Effort)
Chubbs
The drop thing is a farce that got blown out of proportion his contract year he missed all of spring and training camp with the steelers. Im from PGH everyone loved wallace but as soon as he had a rough year catching due to the fact he just hadn't been playing at game speed at all let alone even went to any practices and kinda put him into a rut that whole year. Let me hit you with some knowledge Wallace never dropped more than 4 balls in his first 3 season up until that year because again his timing and rhythm are off and that year he had 5 drops in 6 games including 4 in one game. So all this "he can't catch the ball" is based off a year where he again didn't practice at all in the spring or training camp and talks about contracts etc. I saw the bad year coming from a mile away.
This all goes back to having that bad oline as well which def can factor into drops 100% because when your not getting into a rhythm and your timings off bad things will happen, no diff for Tannehill.
As far as how much heart he has haha how would you know??? Do you know him personally or are you basing that off a few plays maybe he didn't go after the ball a couple times (well he's not a physical wr by any means)? Additionally, if thats what your alluding to were you on the field when that took place so you could see from his vantage point to see if it was catchable possibly with the CB pulling his shirt etc. Theres a lot of factors which us as fans have know idea about or can't see.
Also, how frustrating must it have been when you got all this speed (game breaker) and your O Coord doesn't move you around to get you the ball any way he can, hence getting him into a Rhythm which you need in any sports and in which case he would of had a way better year. Maybe thats why you saw a "lack of effort" cause its frustration more than anything.