I agree that McGuff has done a poor job with talented players. But all of the transfers you mention, as well as the 2016 recruits all signed up to come to tOSU before Mitchell had played a single game during her sophomore year.
We can disagree on this, but the die wasn't cast yet imo. Mitchell was considered a freshman phenom. McGuff was building a powerhouse around her. Once all that talent got to Columbus, the situation was much different. The next two years, McGuff brought in one player, Janai Crooms, ranked 62nd in her class.
I don't know if you watched tOSU's 2nd round game vs Central MI last year in Columbus. I did, and what I saw was C MI blow open a close game as the Buckeyes quit in the 2nd half. To her credit, Mitchell played hard the whole game, but her teammates threw in the towel. There are several ways to interpret that performance, but it seemed obvious to me that tOSU was not a team, but a collection of individuals who were ready for the season to be over.