in an era dominated by offensive guards.
The strategy to take in such an era is to zag and to make sure your own guards are all defensive plusses. Isaiah is the worst defensive guard in the league, on the other hand. Fultz will be a plus.
IT isn't close to the worst defensive guard.
Which old school stat and advanced metric suggest he isn't?
Thomas' defensive rating numbers are all dragged down because Brad deployed him a ton in 3-guard lineups. In the aggregate, all of our configurations with IT+AB+MS posted a horrible DRtg of 115.2. Every other 3-guard lineup combinations involving those three and/or TR were all similarly bad or worse. Basically we were consistently worse than the worst defense in the NBA when we used 3-guard lineups.
In some of those 3-guard lineups, we had huge offensive output and it was a net positive. But overall, they were just barely below breaking even with a 115.0 ORtg (which is really good, but not good enough to overcome the poor defense).
Conversely, 2-guard lineups with, say, just IT + Avery or just IT + MS or just IT+TR were typically league-average dense, while still maintaining top-of-the-league level offense. All of our 2-guard lineups with Isaiah were at least +3 net positive and most were much more than that.
When you cite stats such as DRPM and individual +/- numbers that purport to show that Isaiah is the worst defender in the NBA, keep in mind that those stats are giving a large weight to the horrible 3-guard lineups that we used a lot. And that begs the question, were those 3-guard lineups bad defensively because of Isaiah? Or because they were just bad configurations that put guys in bad mismatches?
For example our most popular 3-guard lineup forced Marcus to defend the 3 and Jae to defend the 4. That had a really horrible DRtg of 116.2. If you remove Marcus, slide Jae back to the 3 and insert any of our bigs in the front court and the DRtg drops to 108-110-ish. That's not because Marcus is a bad defender. That's because he was put in a bad defensive configuration.
And, how did "zagging" with our defensive guards work out against Cleveland?
It won the only game Cleveland has lost in the playoffs so far.
No, Marcus Smart having an insanely anomalous shooting night, along with fat shooting by the whole team won it. That game was not at all won due to "defense". It was won because Marcus shot a ridiculous 70% on threes in a freaky Ray Allen impression and the team overall shot 45% on threes.
And Lebron scoring 11 points in one of the worst, anomalously bad games of his career also won it for us.
Those are not sustainable things. Hence, we lost the remaining games.