Except Derrick pinpointed "3pt shooting", after the Finals, as the one thing he was going to work on this Summer.That’s 3-pt shooting though. There is always going to be short-term year-to year variance in this isolated area……I don’t call that an improvement. Last year he was a little below his career norm and so far this year a little higher. He could easily make 6 of his next 20 three’s then he’s back to last years “regression.”
If he starts missing (which he will) and turtles then he hasn't improved. BUT if he continues to not hesitate, it's fair to say we have seen improvement. It's mostly a body language thing (plus % improvement).
Here is a preseason article that discusses his off-season shooting work with Ben Sullivan and how disruptive last season was with the birth of his child/new surroundings
It's also going to be hard for White to find shots with Tatum, Brown, Brogdon, Horford, Smart all in the pecking order ahead of him. Then he hits the floor with Grant/Hauser (PP sometimes). DW is going to see a ton of open 3s and driving lanes playing with that 2nd unit. He should see his offensive efficiency numbers go up.
On another note, the one thing you have never seen with Derrick is a negative ON/OFF or +/- over a season and wouldn't expect to see that going forward. The dude is an extremely high IQ player, does the dirty work, and takes what the defense gives him on offense.