I was too young to have seen peak DJ. Interesting about his defense. You have him over or at least on the same tier as Moncrief or MJ as a defender? How was he off-ball?
Over Moncrief and Jordan? No. That is the pantheon of great defensive SGs.
On the same level as those two? Sonics/Suns D.J. yes. Celtics D.J not quite but close (he was all-defensive 1st team in 1986-87 as a 32 year old).
You have to remember the times. By the time Dennis Johnson came along in the late 70s the best defensive guard we had seen was either Walt Frazier or Jerry West, maybe Jerry Sloan. After the mid-70s there wasn't really a dominant defensive guard, especially at SG. Until D.J.
From 1976-77 to 1979-80 Seattle was the league's best defensive team (just 98.1 pts/100poss allowed), and Johnson was their acknowledged best defender. Watch some of the Sonics Finals games from 1977-78 and 1978-79 on youtube and you'll hear Brent Musburger slather him with non-stop praise for his defense.