That part exactly. With Fox, Harper and Castle being ballhandlers, Devin not having to dribble the air out of the ball should benefit him (in theory). That way he can save his energy for the defensive end. Fox and Castle being point of attack defenders would make Devin play more help defense, which is his strength.
Offensively the PGs should allow him to play off the ball more and be a catch and shoot threat. Add into that that Devin can put the ball on the floor when teams close out on him as well as abuse bigs on switches and he could be a high end 3-and-D guy in the league. Again in theory. Gotta see if he can actually play that role efficiently and move well enough off the ball.
Devin putting it together would basically fix our starting 3 spot. I don't really like him as a scorer off the bench, cause Keldon seems to be that guy and both of them together are usually a defensive disaster.