2. Perimeter defense
The Dallas Mavericks have had a really spotty defense overall to start the season. As can be expected with any NBA team that is still trying to get fully acclimated together at the start of the season, Dallas has had moments where they've looked really good defensively as well as unbearable to watch.
Lots of Dallas' defensive woes can be attributed to getting out-hustled on the defensive glass for second-chance points, as well as their inability to get back on defense when other teams force turnovers off of lackadaisical Dallas passes.
Dallas' front-court defense has become increasingly stout, with Grant Williams and Dereck Lively II thriving defensively as they get more comfortable within the Mavericks' switch-heavy scheme, but the Mavericks are still having some perimeter defensive issues stemming particularly from their trouble closing out on shooters.
Tim Hardaway Jr. has had one of the best seasons in his career as a defender this season for Dallas, as he's only behind Jalen Brunson for the most charges drawn in the league this season with eight on the year already. Hardaway Jr. has been more stout in one-on-one matchups as well which is a sight for sore eyes, but he still has his deficiencies as a defender.
Couple that with the fact that Josh Green has been playing much more reactive and sporadic on defense, almost as if he's losing the discipline he showcased defensively last year that made him so effective, and it's no wonder that the Mavericks are having some perimeter defensive issues.
Luka Doncic and Kyrie Irving have been playing well on defense to start the year, but they can only be expected to expel so much energy on that end given their workload offensively. If Dallas starts to lean on Dante Exum and Jaden Hardy a little bit more after strong performances in the last few games, it could certainly bolster their ability to stay in front of the NBA's top guards and wings on a nightly basis.