don't see who would be the #1 opposite him. There are some guys on the roster who have potential at OT, but not a sure thing because they are still developing and also they have no experience.
They need either a DE or LB that can pass rush consistently. I like Kelly but he's getting a lot of attention from the offense to be blocked in game planning, they need another good pass rusher, ,maybe even a specialist. I beleive they would like Asiata in this role but he is still way undersized and really hasn't played much, he might need another year.
BYU is tied for last in B12 with 14 sacks and 120th in FBS. Imagine how good the defense could be with a good pass rush.
A CB and a DT isn't a necessity IMO because I believe Alexander and Kabeya will take steps forward and also Tuala should be ready to play a role next season. That being said it wouldn't hurt to add depth.
I always thought that BYU lacked a speed back that could add a wrinkle to the offense, I'm not sure why they don't have that 5'10 185 pound squirrelly back that could bust a big play.