I am no expert of QBs, but after watching the film on McKee and Yankoff, McKee has some wobble to his passes while Yankoff is a little off on how throwing technique (threw off balance or off his back foot a lot, but he did make accurate throws).
McKee looked better as a passer, but Yankoff must be the dual threat QB that Riley spoke of in a recent interview (NSD?) as his running is impressive.
I hate to miss getting a great QB just because of the chance of injuries and transfers, but with the last two QBs, one would think 2018 would be a year the staff could whiff and get away with it (if they weren't able to get any of the QBs mentioned in this thread).
Whoever they recruit and get, I just hope Langs gets all of his QBs to excel while at NU.