You're setting a number limit for your satisfaction that they must meet on the current count of 4 stars they've offered so far? That's silly.
The top end of recruiting isn't necessarily where BYU needs to improve. They've been ok there. They need to boost what would be considered the lower end of talent, and as far as a percentage, probably the "lower" half to even 2/3 sometimes. Those are the guys who fill out the depth chart. Those are the spots where they should try to fill a few with nothing but really solid plug-n-play athletes who could be used in a number of spots. Put them where needed. Or guys who might be raw but have a much higher athletic ceiling.
BYU is not going to be handing a handful more 4 stars every year. They're going to get better by still snagging a few, but filling out the rest of the class with better quality guys.