2. Wing Rebounding
It's no secret that the Mavericks struggled to collect rebounds last season. They finished second-last in the Association in both rebounds per game (47.5) and rebounding percentage (47.3%), forcing them to add names like Lively, Prosper, and Richaun Holmes during the offseason.
While the trio should be productive grabbing boards, their addition doesn't address the Mavericks' need for better rebounding from wing players.
And while Williams is capable of playing small forward minutes, he'll spend the majority season at the 4.
While Irving averaged 5.1 RPG, he's only 6-foot-2 and can't be expected to win every battle against bigger players. Both Josh Green and Tim Hardaway Jr. averaged just over three rebounds per outing, but neither man is exactly known for their rebounding.
The Western Conference is stacked with elite wings — LeBron James, Kevin Durant, Kawhi Leonard, etc. — and the Mavs can't expect to be a top team unless this issue is addressed. That isn't to say that they need to add another superstar, but bringing in another competent wing defender would go a long way.