I think it's often the case that Dunn does the least bad, and that's a big thing when it comes to our PG's. When it comes to doing the least bad for this team, often that means not taking shots away from Lauri. If you look at the four factors, what's causing that strong ORTG with Dunn is the eFG%. Some of that can be noise, but IMO, what's really happening is that Lauri is getting more shots with Dunn than without him. The offense is terrific with Dunn+Lauri, not so great when it's Dunn without Lauri. THT and Sexton naturally use more possessions than Dunn. Those possessions have to go somewhere.
Lauri's usage and TS with:
Dunn: 28% / 66.5%
THT: 24.6% / 62.2%
Sexton: 24.4% / 61%
The difference in TS may just be noise/luck, so I'm not reading to much into that. But the uptick in usage for Lauri with Dunn....yeah I buy that.
Also worth noting, all of the other scoring guards (THT, Sexton, JC, Keyonte) shoot the ball extremely well from 3FG with Dunn. I think I'll chalk that up more to randomness than Dunn being an extremely good setup guy, but that's a big contributor to his strong ORTG. Methinks there is some truth to Dunn to being a stabilizer, especially compared to the other guards, but it's probably being overstated in the numbers right now. He's the most limited, but probably the one who does the least amount of damage on both ends.