My assessment of the major shortcoming last night was defensive, not offensive. When we had our starting guards out there, our motion looked crisp and decisions were generally correct. Brown had some stupid "dribble into traffic and turn it over" plays, as he does, and Tatum threw one or two away, but we didn't have a deluge of turnover issues the way we did vs Atlanta (there's no Dyson Daniels on the Cavs, thankfully). Our shot selection looked pretty good, though we did make a bunch of heavily contested shots.
But on defense, every bit of our help on drives by their guards appeared to be late. We ended up on the short end of 2v1s on the perimeter a lot, as we got lost in some switches and ended up giving up wide open Merrill 3s, which I can assure everyone was not the game plan. Mitchell has a near-unique ability to stop a drive, hesitate, or blow by people, depending on positioning, that is deadly - but we didn't appear to be strategizing to take anything in particular away (i.e. once he got past the 3 point line, which we mostly chased him off of, we seemed unable to prevent a layup). Whatever part of our strategy was intended to neutralize Allen and Mobley largely worked - we got a ton of contested rebounds, too, which Tony Dobbins highlighted as the main positive in the first half. But if we're working hard to get a few buckets in the 4th and then every time we go down the floor, Garland or Mitchell just drive to the hoop and get a layup within 6 seconds, something is very wrong. Maybe part of that wrongness is how we were being officiated, such that Mitchell could grift a few calls Dame or Harden-style and our guys were gun-shy, but at most that was only part of the problem. There were a few plays where things worked (e.g. Hauser getting cooked by Mitchell 3 times in a row, but then holding up and getting a miss on a 15-footer the 4th time), but it felt like they were not part of long stretches of us playing good defense, they were occasional moments of focus or great individual plays (like the blocks). Put differently, our individual defenders were OK, but our team defense was lacking.
If I had a few hours and a byline on CelticsBlog, I'd put up some clips and show the breakdowns (or, alternatively, the choices we were making to give up X to take away Y, which mostly did not appear to pay off). But just watch the highlights package upthread and you'll see plenty of them. The comparison to the ECSF in May, with basically the exact same personnel on both sides, is striking.