These are for the 28 games played to begin the 2015 - 2016 season when Burks was healthy. He returned to play 3 games in April and I didn't bother to re-run the report to add those numbers.
Average defender distance on 3pt shots:
Alec Burks - 6.9 ft 29-75 38.6%
Gordon Hayward - 6.2 ft 51-128 39.8%
Rodney Hood - 5.5 ft 39-123 31.7%
On average Burks had an extra 18 inches of space over Rodney Hood.