There is a not-so-easy way to theoretically improve a team's defense. Make your team up of longer, better athletes than your opponents. There are some teams who do this very well, like Kentucky for instance. This past season, Kentucky had above average height and length than their opponents, except for one or two guards. Its front line players averaged 6-9 to 7-0 feet tall. This caused many problems for UK opponents. Now, where is BYU to find multiple seven footers that run like gazelles and can jump over cars?
That is the crux of this problem. BYU has many recruiting limitations that are documented elsewhere, and even if they didn't, BYU is not currently a program that is attracting elite talent like the Dukes (who was not particularly great on the defensive end), Kentuckys, Arizonas, etc. So how does BYU take a leap defensively when they may be playing at a disadvantage athletically?
The one thing I noticed in the 2015 NCAA Tournament was that when teams needed stops, they instantly became more physical. Now, some might say physicality has not been lacking from some BYU players, think Bronson Kaufusi body slamming Kelly Olynyk or Luke Worthington picking up 4 fouls in 5 minutes of play. Those are not physical plays, they are silly plays. Basketball physicality is not about beating up someone to get your way. It is establishing your position before you have to start pushing and shoving and committing silly fouls to establish yourself or to set a tone.
This defensive way often actually starts with the guard line. It is hard to be physical as a guard. You can't hand check or body bump ball-handlers anymore, which limits what you can do to stop your opponent. But for guards, physicality means picking up the ball-handler earlier, and bodying up your man when he cuts -- think what everyone does to Tyler Haws when he is running around trying to get open. This throws off the timing of cuts, passes, and therefore shooters. This can then ruin their rhythm, which increases the chance of producing a missed shot.
For post players, it means meeting your man early before he establishes his position on the block. Remember when Przemek Karnowski made BYU's big men look like little boys in the post? This could have been avoided if BYU post players did not let him take his position under the basket and then decide to fight. Start bodying him up around the free throw line so when he goes to seal, he establishes position a few feet further from the basket. If you have ever played in the post, you understand how big a deal those few feet can be when you are making moves that are normally performed at 5 feet away from the basket are now 8 or 10 feet away.
Although it is very simple to say "do this and you will have results," it is really apparent that BYU is not tough on defense. Defense is hard. All the rules are stacked against you. Sometimes, it downright hurts when you get in your stance and are chasing someone or are fighting for position down low -- especially with a brutally-long 35 second shot clock. BYU teams can score, they have proven that. But even in an offense-driven game, the team that wins is the one that can stop or disrupt its opponent enough key times. BYU needs to improve on defense if it truly wants to contend with Gonzaga in the WCC and advance past the first weekend in the NCAA tournament.
What changes might be in store with the addition of Quincy Lewis to the coaching staff? Time will tell if his noted defensive coaching abilities will translate back to the college game where he once coached before and if he can be a part of BYU's defensive solutions.