Vernon--and it's not close. Put a healthy and out-of-trouble Vernon opposite Chickillo, and watch our DL become special when getting after the QB. Instead, Shayon Green's opposite Chick. So...there's that, I guess. Green might turn out to be really good for us this year, but I would have felt a lot better with Vernon at DE.
Streeter/Miller are close in my eyes...I'd say Miller 2nd just because he was dominant as a homerun threat at RB as anyone in CFB last season. However, his shoulder injuries held him back. If I could get the promise in this hypothetical situation that Miller would be completely healthy this season for us, I'd definitely take him back. That's not saying I don't have faith in Duke/James/Clements/Crawford though...because I do. I just don't think that anyone can be as complete a back and be explosive at the same time like Miller was last season.
Streeter will be missed in the red zone and on long 3rd downs where everyone else is covered and Morris just has to throw it up to someone who can highpoint the ball better than anyone else on the field. Streeter bailed Jacory out a bunch last season with bad throws, and ditto for Morris on a couple of throws in the Maryland game (though, one can definitely argue that he hurt us on that last play that went for a pick-six...if he comes back to the ball on that route, at least it's pass interference if he gets run over and doesn't make the catch).