I'd say he was, but he ran too loose of a ship. That's what has gotten USC in trouble. An agent got to Reggie Bush and he was the one who paid him, but Carroll, the rest of the USC coaching staff, and the administration either turned the blind eye or didn't make enough of an effort to regulate things.
Otherwise, I'd say he was a very good coach. I'd definitely take him as UT's HC, given that Hamilton and the compliance office keeps a close eye on them. But given the complaints Kiffin and Co. had about our compliance office being to forthcoming about minor violations, I'd say they'd do a better job. Especially since UT isn't to the SEC as USC is to the Pac-10, and Slive wouldn't be so hesitant to punish.
From my brief views into the USC culture, it appears to be a giant circle jerk session. But they can't plead ignorance and get away with it, and apparently they've been blindsided to the point that they're making villains of everyone but themselves in order to rationalize the situation they made for themselves - that's been apparent from their AD making the "The NCAA is jealous because they want to be Trojans and aren't" (or whatever he said) down to the fanbase message board junkies who are playing the victim to the NCAA's malicious intent.