Giving up 129 points in regulation can't be acceptable for this group. Our defense has to improve, and it has to start at the top with Tatum and Brown... because IMHO that's where the biggest dropoff has come. Tatum went from an above average defender to a mediocre one. Brown has always been a bit inconsistent - generally excellent on-ball and spotty off-ball - but he has gotten worse in both categories this season. He's legitimately a poor overall defender right now.
We have the tools to be a very good defensive team. Instead we're a bad one, and fixing that is one of the things that must happen if we are going to contend at any point within the next few seasons. Our stars have to lead that charge.