This is what I disagree with. Not using him as a threat in the passing game because he's not a reliable blockers is extremely shortsighted. By using him as a threat down the seam or splitting him out wide, you're taking a LBer out of the play. That's just as effective as blocking at the 2nd level. For example:
88 11 77 55 72 70 71 80 13
4 21
A team has to come out in nickel against this formation. With just one route, let's say a skinny post down the seam, Gathers opens up 3 things from RPO.
1: 5-man defensive box if LB supports covering 80 downfield (run)
2: Seam route pass if 80 is in single coverage, body position against the safety is built in
3: Man coverage on outside WR, depending on safety rotation
You're getting 3 legitimate options from 1 route simply because of Gathers' size, and he hasn't had to throw a block yet. Witten couldn't do this the last couple of years, and this is basic, easy, RPO. You could run this play 5 times a game, and that's not accounting for how effective he can be in the red zone.
If Gathers can't command a double team down the seam, then he has no place in the NFL, but he can absolutely be a weapon in this offense, regardless of how well he can block.