I love Matt Thomas, and if senior Matt was going to be on the squad next year, we'd probably project him to lead the team in scoring as the featured SG and he'd be the face of the program right now far more than he was in reality being "stuck" behind some all-time personalities like Georges and Naz.
That being said, I wouldn't have called him a defensive "stopper" on the same level as Chris Babb and Gabe Kalscheur. Matt went from a heralded SG recruit who, well, couldn't shoot and was bad at defense to one of the best shooters in school history (with the prettiest form I've ever seen from a Cyclone... so quick and so smooth...) who was at least a plus defender in the Big 12 but not really a true stopper.
I've watched that comeback game against Iowa a few times now. I know Matt takes the credit, but Georges was actually the one guarding Uthoff when he came back down to Earth. I don't think it was so much the defense as Uthoff had the half of his life channeling Bird and then the magic potion wore off.
He was a starter as a true freshman. He was fourth on the team in scoring behind Garrett, JVG, and Uncle Jake and second on the team in rebounding after Uncle Jake. Is that really a "role player?"
That being said, going from a low-end starter in the Big 12 (who was starting mostly because of a complete roster reset after McDermott left and Fred came in) to CPOTY is still impressive.
When Matty T. came into form his senior year it was more like a 'he's arrived' then 'out of nowhere'. Expectations iirc were huge for him coming out of high school and it took some time for him to just play and react instead of worrying about the next step.
Of note, he was the one player that looked like they knew he was in a one and done situation that awful March day in 2015, his sophomore year.
I saw Ejim play on Fred's first team over Thanksgiving weekend and his athleticism stood out, was just raw is all. That said I wouldn't have predicted he turn into what he did.