IMO SJD is a JAG and he's playing like I said he would. He doesn't really command a double team and he doesn't even control his A gap. Too many times he simply is pushed out of the way. He can't even beat most centers one on one. They pulled him often and played Brockers at NT occasionally.
Smart is another JAG who does nothing on his own. I would rather see Gaines in rotation with AD if you aren't going to play Greg at NT. At least you would have a guy who gets penetration and not simply a body on the field.