The defense can easily be much better - but they will need better players. They relied a lot on fouling. And that hurt the offense, as they went up against set defenses a lot. Once they can defend without fouling so much they can convert defense to offense much better.
I liked what I saw of the offense, as it began to develop. I love the importance placed on execution, screens and cuts. To me, just getting a hint of that was as good as the defensive improvement. Get this man some more players and things will be good. We desperately need to see some guys on the court that can produce as much excitement as the coaching. And from there we can see for sure if he's the real deal.