There is really nothing to be concerned about with next years QB's.
There will be no need for Leach to get a grad transfer.
1. Cooper will be a 4 star QB, that will probably get some back up snaps, time to improve, would be a Reshirt Sophmore(The equivalent to a 3rd year True Junior). Also Falk was the same, a Redshirt Sophmore, when he started, did well.
2. Cruz a 3 star by some recruiting services, a 4 star by other recruiting services. Has looked good so far in Spring Football. Would be a Redshirt Freshman(equivalent of a 2nd year True Sophmore)
3. Bledsoe, has looked good in Spring football, has had some back up snaps. Would be a Redshirt Senior(5th year SR Walk On)
Angelos. Dont know much about him, except that he likely is a walk on.
Either, 1. Cooper, 2 Cruz, 3. Bledsoe, will likely be the starter, and whichever of the 3 will likely not only be the starter, but likely will do a good job as the starter, or at least well enough that the OL, Borghi, WR's, Defense, all combined will, would probably win about 7,8,9,10 games for WSU.
So because of that, Leach would probably not need to go get another Grad Transfer.
And even if he Leach did need to go get a grad transfer, because, if the current next years QB's were to if, probably get about only 5,6,7 wins, instead of 8,9,10, wins, if that were to be the case, it might be better to only have the 5,6 wins, then to risk not getting good future QB recruits not wanting to commit, sign with WSU, because of 3 straight years of Leach getting a grad transfer.
But really everything should be just fine next year.