It was nice to have a QB who doesn't throw his best while rolling out (i.e. he's able to see over his line), and if Golson was going to run a lot, Kiel was going to be in there a decent amount. Kayo pointed out on Cartier that it's not good to have the hope that the guy ahead of you goes down, and I think that's a good way to look at it.
However, I think you have to look at it as an inevatibility with Golson... especially given the new helmet rule and the (justified) hypersensitivity to concussions these days. If Kiel came in a big game and played well, I think it's entirely possible he could have passed Golson. Situations like that have happened constantly; the starter looks good, but when he gets hurt and the next guy looks even better he gets unseated.
I jus don't understand the timing on Kiel's transfer. If it was at the end of spring and it was apparent Zaire was ahead of him, so be it. But now? I think Zaire was certain to redshirt before this (I hope he doesn't now) so I don't understand why he didn't see this through one fall as well.