Here are what I would say are the basic problems with Hewitt over the second half of his tenure at GT. Whether you want to classify these as X's and O's is up to you.
1. A lack of player development, especially with guards. Pretty straightforward, but the guys that came in never seemed to be any better when they left than they were when they arrived, which leads to...
2. A lack of cohesiveness on offense. Players made stupid mistakes, were out of position, or just generally seemed unaware of what they were supposed to be doing on the offensive end. Many many stupid shots. Gani Lawal made up for this by being a rebounding machine (as did Favors in his one year) but overall the offense lacked flow and purpose.
3. The aspect that worries me most about the hire is that over the course of the last few years Hewitt seemed to become frustrated to the point that it seemed like he had given up, or as if he had simply been beaten into submission. Litos brought this up in his recent caahoops post and it is my biggest concern. Does Paul Hewitt still have whatever fire he had when he first came to GT? Does he still have the passion to get the players to play hard. His teams at GT the last couple of years rarely showed sustained effort. And that is a big problem. Maybe the change of scenery helps Hewitt get back whatever he lost. But that is my biggest concern about him.