You know why YAC matters?
It shows one of a few things:
1) your receiver is able to make moves in the open-field, which is demoralizing to the opposition.
2) your receivers are getting a lot of separation to make the catch and keep moving, which is demoralizing to the opposition.
3) your receivers are schemed into a position to be more open than they should... say it with me now... which is demoralizing to the opposition.
Those big plays are great and all, I love me a 50 yard bomb as much as the next person watching football, but watching a TE, a RB, a Deebo (nikka ain't a WR. Cuh a race car with a cow-catcher and tank treads) take a 5 yard catch and turn it into 30+ is miserable. Seeing it happen from one person was bad enough, when Kittle was running over dudes, but knowing you can't rotate coverage away from one side toward him because there's someone lined up on the other side who might do the same thing is depressing.
The problem is, you have to have the threat of hurting a team that decides they're gonna neutralize that by going 8+ in the box. You have to, especially as a run-first team, because the same way you neutralize those running lanes is the same way you take away those underneath routes, and those two things can't be a team's whole offensive identity without it being eventually stifled.
Deep balls must be thrown; at least once a game. And not on 3rd and forever, either. Not saying you gotta hit all those deep balls. But you at least have to make them worried about what might happen if you do. Goodwin were he not injured constantly woulda been a good gadget piece for stuff like that. The team should definitely look into a smaller-school WR who gets in that 4.3 range at the combine, even way late round. Someone to open the game up, force some spacing.