On paper it's a weaker roster, but we never really got to see the "on paper" version of the team with Gordon Hayward except in limited stretches.
What concerns me about the state of the roster right now:
The bench is lacking in an established wing.
As things stand we would need one of Langford, Nesmith, or Ojeleye to turn into a reliable 15-20 minute backup 2/3. You would hope that two recent lottery picks could manage that, but Langford is injured again and Nesmith is a total question mark. Semi, I think, is solidly a third string caliber player at best.
What I feel good about with this roster compared to previous years:
The hierarchy of the team is clear from day one.
This is Tatum's team, with Kemba and Brown as the secondary and tertiary scoring options, depending on who's got it going and what the matchup is. Unlike previous years, there's no longer any question on this team about who is the most important player, who should be taking the most shots, who the offense revolves around, etc.
Also:
The Celts should have 48 minutes of solid center play.
Theis has demonstrated that he can be a solid starter even in the playoffs, and that he fits with the starting lineup. Robert Williams has demonstrated that he can be very productive on both ends when given minutes, provided he can limit his mental lapses. Tristan Thompson is a lob threat and rim runner on offense who can move his feet defending the pick and roll and clean the glass on the other end. Between those three guys, the center position is well stocked, and that's without acknowledging the possibility of using Grant Williams as a small ball 5.