Poor roster construction that they just keep compounding by not adding actual NBA players. As I've been saying for months, 1/3 of your team can't be journeyman on the verge or leaving the league, or untested 2nd round picks or undrafted players who have done nothing in the league.
Poor roster construction? Cmon man. They’re a top 5-10 team in the league coming off a finals appearance. They’re 3-1. I know it’s your thing to use hyperbole, but why not just say that you didn’t like how they rounded out the bench? They clearly don’t have a poor roster as is currently constructed.
They have a poorly constructed roster. Some of it is fine, but some of it is not. The parts that are fine are things like Tatum and Brown both being at their best at SF, not really an issue to move Brown to SG and keep Tatum at SF. Not having a true PG, also is fine as Smart, White, and Brogdon are all excellent players and can make it work. But a part of the problem on the roster is having Brogdon, White, and to a lesser extent Pritchard on the team which means that 3 of the 4 best bench players all basically play the same position. And Brogdon and White, collectively make a supermax type contract. That is a lot of money tied up in backups that play the same position.
There also isn't a proven back up wing. Sure Brogdon can play there in a pinch as can Grant, but they aren't guys that should be playing on the wing very much. Hauser just isn't ready for the kind of role he is being asked to play. He will certainly have flashes, but at critical moments, you shouldn't have to rely on Hauser, and frankly when Brown gets hurt and misses 15 games like he does every year, the team is going to see a real effect of not having a quality back-up wing.
But the real problem is the interior. The big man rotation is awful. Even before Gallinari went down, it was clear that it was awful. Grant is fine, but you can't claim you are a contender and then have Vonleh, Griffin, and Kornet be your bench big men, especially when your starters are Rob "Glass" Williams and Al "Walking Stick" Horford.
Boston will not last the season as a top tier team with the roster as it is presently constructed. Tatum and Brown are good enough in spurts to carry the team, but they can't do it all season, especially when you are asking Tatum to play PF a lot more. He shouldn't be playing big minutes at PF, it will wear him down even more, especially when you are having them play 37 or so mpg. That is just too much, especially this early in the season.
And all of this was easy to see and predict. It isn't like we've had a slew of unexpected injuries. Williams, Horford, and Gallinari always get hurt and miss time. The plan just wasn't there for it to happen. And because Rob is going to miss so much time (and Gallo is out for the year), the wear and tear is going to accumulate as the season goes on.
So yes, the roster is poorly constructed. There is obviously a lot of talent, but the poor roster construction will catch up to the team at some point, if it hasn't already.
And the real shame of it all, is the C's had a very large asset that could have been used to fix some of these issues, but just didn't do it. Even taking that aside, the team could have signed veterans that you could rely on more in a pinch, but instead signed Kornet, Vonleh, and Jackson (Griffin is at least a veteran and I have no issue taking a flyer on Hauser, he just shouldn't be the back-up SF).