I've changed my mind a little bit on this. Last night I re-watched the 2014 win over Wisconsin, which has been on my DVR forever. Not only was it striking how Austin Hollins was in the middle of the action so often (even though he didn't score much that game), but the team overall was just smarter. You saw few if any easy bunnies due to defensive mistakes. Malik Smith and Oto logged a lot of minutes that game, and they just looked like they knew what they were doing on both ends of the floor. They talked a lot.
I tend to forget about Malik because of his awful shooting slump at the end of the year, but he also had a real tough edge and swagger to his game, he was aggressive, and he also knew where he was supposed to be. This year's team missed him, or someone like him. Deandre of course looked much more confident, but it partly may have had to do with the players around him. Also, I was reminded that a big reason we beat Wiscy was Kaminsky picked up 2 dumb fouls in the first 2 minutes of the game and sat the entire rest of the half. He never really got into a groove after that. In other words, we were a bit lucky.
In short, what I'm trying to say is that I think we lost more than I thought we did from last year, both physically and mentally. The guys we lost were more important than I realized, and it wasn't just Austin.