Giddens was also offered by: Kansas, Indiana, Maryland, Louisville, and Arizona, to name a few of the marquee programs. He was the #8 center in the class, top 50 overall.
Mitchell was offered by: Kansas, Baylor, Florida, Oregon, Texas, to name a few. While he was outside of the top 100, he still had good offers.
You cannot use hindsight to justify recruiting certain players. Giddens was never going to carry the offense, at least not for a few years. He was a defensive player and a rebounder, and was not going to be expected to contribute a ton offensively. There are a lot of players out there like him, plenty have passed through the doors of the Schott and plenty into the NBA (Dallas Lauderdale comes to mind, Tristan Thompson for the Cavs is a similar role). Mitchell is a very good athlete with good passing vision and the fact that he sat out a year of high school ball as well as the start to the season was evident in a rough freshman year.
If we never gave players a chance to develop, then we should never have recruited Jon Diebler. He's now the all-time 3-pt leader at OSU...who shot 29% from 3 his freshman while taking nearly 5 a game. If you want to continue to argue what Matta SHOULD HAVE known when recruiting these guys, then I think you should probably be paid millions of dollars per year to coach and recruit these guys.