I think BYU needs to be quite a bit more selective in bringing in those guys. With the change in missionary age, I think going after quite a few of them this year was okay because BYU needed immediate depth that it couldn't get any other way.
I think it can work fine for WRs, DLs, RBs and maybe CBs. But not so much for OLs, Safeties and LBs. The complexity of those latter positions makes it tough for a guy to come in and pick things up sufficiently in one year to really contribute. If Harvey Jackson had another year, I think he'd compete for a starting position, but I think he has struggle to pick up the D.