While ypc is a useful stat, I think.it is also wise to consider the percentage of runs that go for over 4.0 yards. Throw out garbage time stats and stats against bad defenses, so that is most of the Titans and Texans runs.
If you can consistently get 4.0 yards a cary, you can be a successful running team. If not, they you will always have an offense that stutters and punts a lot.
Miller is a home run hitting back, but I have been increasingly impressed with his effort to make yards after contact, especially under Campbell. But if the OL cannot open the hole and the RB follow his blocks, the 4.0 yard consistency simply fails. One big run helps the ypc stat, but it doesn't really change the need for consistent down after down production needed for a running team to be successful.
We simply are not built across the OL to be a running team. Thomas is garbage, James is powder puff, Douglas is a rookie so ill give him time, but Turner is beyond raw.
We have no Marshall Yana types. We have no Zack Martin types. Our guys are pathetically bad at technique. We are not going to consistently generate leverage and power. Moving people simply isn't our strength.
..... And IMHO, that is what needs to change.