Yeah. Blame the players because the coach can't coach offense. Crean's players couldn't guard so that's the players fault? You can't have it both ways. Devonte magically improved as a shooter when he finally started to catch and shoot instead of shooting off the dribble.
You need to understand the game a little better. Teams are good offensively because they have good offensive players, not because they run some magical offense that can't be defended. That is a universal truth of basketball at every level from grade school to the NBA. The job of a coach at the college level is to provide instruction and technical help that make individual players better. There has never been an offense designed in the history of the game that can take 5 skill-deficient players and make them a good offensive team. Conversely, there are a dozen different offensive systems that can succeed at a high level with skilled offensive players. Calipari's dribble-drive, Bob Knight's true motion, Bo Ryan's swing, Dick/Tony Bennett's mover-blocker, John Wooden/Denny Crum's high-post, are all championship-caliber offenses with the right players - and all suck if you try to run them with kids who lack ball skills.
Coaching does come into play in understanding how to attack a zone or a junk defense, or how to counter specific defensive tactics like double-teams, traps, etc. Tom Crean was certainly no genius when it came to that. In fairness though, I never saw one of his teams be any worse than Bob Knight's embarrassing effort vs Pepperdine in the NCAAT. It looked as though he hadn't watched a second of film and had no idea what Pepperdine did on defense. At that stage in his tenure, I'm not sure that wasn't the case.
OTOH, defense is the true reflection of great coaching. Being able to take away the strengths of opponent's individual players, getting 5 people to work together to force the ball into bad spots, understanding and teaching complex concepts like when to help, proper body positioning and placement, unraveling and spoiling opponent's tendencies, etc.
Guys that often get less credit than they deserve because they win big with great talent are usually damn good defensive coaches. Calipari, Pitino, Boeheim come to mind. Bob Knight recruited very good offensive players and made great defensive teams. He didn't turn chicken shit into chicken salad. Izzo, Bo Ryan, Jay Wright, Coach K did/do the same. When John Beilein realized he had to get his teams one level higher to contend for championships he brought in someone to help him with defense.
If Tom Crean ever decides to subvert his ego and overcome his personal insecurity about getting the credit, he might get to that level. At IU, he surrounded himself with unimpressive assistants who wouldn't challenge his thinking and didn't pose a threat to his need to get the credit. There's a reason none of those guys were getting head coaching offers even when IU was winning B1G championships and being ranked in the top ten.
It's really pretty simple. To win at a high level, Archie has to recruit and develop better offensive players. The guy knows defense. Watching the development of Juwan Morgan and Al Durham gives me hope. All of our players need to work to improve between now and next season, and we need a true shooter. Defending is all effort and concentration if it has been taught correctly. Archie is one of the best in the game at teaching defense.
Crean, on the other hand has to get some clue as to how to teach defense and get kids to play it or he will be at Georgia exactly what he was at IU. It would also benefit him to be able to get his players to understand the importance of not pissing away 25 possessions a game by playing too fast and making bad decisions.