I see the problems being many and not just one but here they are, in no particular order:
- Cold shooting. They lead the league in wide open shots but have completed a horrid percentage of those shots. The offense is creating the opportunities but just not making them.
- Lack of offensive balance. The team needs to drive with a purpose to finish at the rim rather than just kick out for a three pointer. Just way too many three pointers. This is easily remedied with more pick and roll offense, especially with Horford or Baynes running to the rim. Theis is great at this. He has been missed.
- Lack of cohesion with the starters. Clearly everyone hasn't figured out their role yet and that is compounded with Hayward being far from the player he used to be. Tatum is not a PF and has transformed his game for the worse with mid range iso ball. Brown started in an awful slump and Kyrie seems to be hesitant, until recently, of being the alpha man on offense.
- Lack of scoring off the bench except for Morris. Theis was having a good year until getting hurt but other than he and Morris, not one player on the bench is shooting well or giving the team any type of consistent scoring.
- Lack of a player that can play defense against the bigger more talented centers in the league. They need someone who can take on the Jokics, Goberts, Embiids, etc. in the league. That may be Robert Williams in two years but it isn't now and Horford has not been able to contain those bigger talented centers in the NBA.