Stats don't tell the whole story, especially when it comes to big men. Look at the first half, SMU goes on a 10-3 run with Vogt in the game. We try to press, but SMU just throws it in to the guy who Vogt is covering.
Then Diarra comes into the game. We immediately force back-to-back TO's. Did Diarra force the TO's? No. But he did guard his man (and provide some help to others). Instead of SMU having an easy outlet pass to their big against the press, all of their players were being guarded and it led to them making mistakes.
Just one small example of how Diarra (and Eason) impact the game in many more ways than Vogt that don't show up on the stat sheet.
I've watched pretty much every UC game of every season for the last 5+ years and watch a fair amount of college basketball outside of UC (mostly AAC games, but also some UCLA and WVU as well as top teams). Diarra is excellent at cutting off drives and pick-and-roll defense. Earlier this year Brannen said Diarra graded out as elite in pick-and-roll defense in practice. It's a small thing, but extremely valuable, even at the pro-level. If he cuts guys off before they get to the basket or take a shot, he doesn't get a chance at a block, but it's a bigger defensive impact.
Diarra has a lot to work on, but nothing that's not correctable. Needs to get better at defending 1-vs-1 against another big, to commit fewer silly fouls, get more comfortable on offense among other things. Given he has relatively little playing time, it will probably be corrected with playing time. Look at our bugs under Cronin, they had a history of being foul prone and making silly mistakes, then correcting it once they became starters and got some experience under their belts.
Diarra may not become a star, but he's not too far from becoming an elite defender. And from a center that's far more valuable than offense. Though ideally you want a guy like Eason - who can do both. But I'm not sure Eason has the size (nor desire) to be a long term starter at center.