Definitely.
One of the big problems is that the Celtics lack players who great weapons without the basketball. They all want the ball in their hands.
Part of what makes the Warriors so special is Klay and Steph complete upend a defense without even touching the ball. Opponents are constantly worried about them. They are such lethal shooters they cannot afford to forget about them. Klay and Steph maximize this further by doing a huge amount of running off the ball. Constantly challenging opponents team defense == and this is without the basketball!
Jaylen Brown, Jayson Tatum, Gordon Hayward, Kemba Walker are not this type of player. They all want to touch the ball. That is when they attack. That is how they know how to impact a game offensively.
Kemba is one of the most high usage ball-handlers in the league. Tatum and Jaylen are both not well-rounded offensive players. They are works in progress whose strengths & weaknesses will not be well served by seeing so little of the ball.
Hayward is the best of them in terms of playing without the ball. He is smart at moving without the ball and knows how to create some advantages for himself. However, he needs a lot of the basketball to be a high end player. He is a guy who is good at almost everything offensively but not a guy who is great at anything. He needs to be able to take part in all different ways of attacking in order to maximize his contributions. That means touching the ball a lot. Running PnRs. Driving. Attacking. If he is forced off the ball too much, you don't get the All-Star Gordon Hayward. You get the 12-15ppg role player Hayward.
Kanter is good without the ball. He creates opportunities for himself. But he is also selfish with the ball whenever he does get it. He doesn't create for teammates and he takes a lot of shots (shots per minute) for a guy who is the 5th option.
This is NOT a team designed to be effective in team offense. This is a group of individual players who are highly talented individual offensive players. Not TEAM offensive players.
TP for an excellent post. You highlighted legitimate concerns that have nothing to do with attitude or chemistry. Stevens needs to find a way to get these guys to play with a sense of purpose, even when they don't have the ball in their hands. I'll post my thoughts on individual players.
Kemba Walker: He's been ball dominant out of necessity. The good news is that Walker posted excellent catch and shoot percentages (46% beyond the arc from 2015-17) until Nicholas Batum started to break down. Batum was the primarily facilitator for the Hornets during his prime. Walkers' off-ball percentages began to decline in unison with Batums' usage rate.
We saw flashes of Kemba running off screens when he torched us last season. I'm optimistic that Brad will run more sets that free up Walker away from the ball. Most importantly, Walker will show a willingness to execute the game plan on a nightly basis.
Gordon Hayward: I see Hayward becoming the primary facilitator within the offense. This can work as long as he regains most of his pre-injury scoring ability. It's difficult to facilitate from the perimeter if the defense doesn't view you as a scoring threat.
Jaylen Brown: There's no secrets with Brown. He can drive, catch and shoot, finish in transition, and hit fade away jumpers from 10-12 feet. Unfortunately, he's yet to show an ability to read defenses and make the right basketball play with any level of consistency. He isn't deserving of more touches until he improves in this area.
Jayson Tatum: As others have mentioned, Tatum needs to get away from the iso mid-range jumpers. A small dose of mid-range shots is fine, as long as he's shooting over smaller defenders from his sweet spots. Aside from that, Tatum needs to get stronger and attack the basket with a sense of urgency.