I wouldn't get too excited about that. Paul George is still a better defender and a MUCH better offensive player. He's also a max player and wasn't available.
As I stated in a previous post, these play type stats suffer from small sample sizes. In some play types, even a full season's worth of data produces a very small sample size. Because of this, they are also dependent on position, role, defensive assignment and quality of opponent.
For example, Paul George is a bigger player. Basketball-reference still lists him as a SF, but he played 39% of his minutes last season at PF (in the playoffs, he played 67% of his minutes at PF). So, that means, for example, when IND plays CLE, Paul George is tasked with guarding LeBron James. Not so for Evan Turner, he ends up guarding a smaller, perimeter player, like J.R. Smith (in this case). Obviously, LeBron James is a MUCH better offensive player than J.R. Smith, a one-dimensional, streaky shooter.
So, Paul George could actually do a good job on LeBron and hold him below his season scoring average, but still get "lit up" for 25 points. Because Smith runs hot and cold, he could easily end up going 2-9 from 3-point range for 6 points. Was that Turner's defense, or Smith's streaky shooting? Hard to say, but at the end of the day, it makes Turner look like a defensive stud, whether he deserves the credit or not. And, because the sample sizes are so small, one exceptionally cold shooting night from a volume shooter like Smith can have a statistically significant impact on Turner's play type defensive numbers.
Point being, don't read TOO much into these stats. As I said earlier, they are somewhat useful, and certainly interesting, for players who play similar minutes and similar roles. But, you still need to look at other advanced stats, defensive assignment, quality of opponent, use the eye test, and most of all, common sense. I'm thrilled we got Evan Turner, he's a good defender and a good distributor - TWO things this team needed. Still, I'd take Paul George in a heartbeat, for his defense alone, over Evan Turner. And, I think pretty much every GM in the league would too, if given that option.
Edit: Here's a few more. more established (but not necessarily more "accurate" defensive metrics comparing George and Turner):
DRtg:
Paul George:
2015-16 = 101
Career = 99
Evan Turner:
2015-16 = 104
Career = 105
DWS:
Paul George:
2015-16 = 4.8
Career = 22.8
Evan Turner:
2015-16 = 3.0
Career = 14.8
DBPM:
Paul George:
2015-16 = 1.0
Career = 1.8
Evan Turner:
2015-16 = 1.3
Career = 1.5
STL/G:
Paul George:
2015-16 = 1.9
Career = 1.7
Evan Turner:
2015-16 = 1.0
Career = 0.8
STL%
Paul George:
2015-16 = 2.7
Career = 2.7
Evan Turner:
2015-16 = 1.7
Career = 1.5
Opponent PER (from 82games.com):
Paul George:
2015-16 = 14.2
2014-15 = 6.1 (small sample size, only played 6 games due to injury)
2013-14 = 12.3
2012-13 = 11.2
Evan Turner:
2015-16 = 12.2
2014-15 = 14.4
2013-14 = 15.8 IND, 15.0 PHI
2012-13 = 15.4
George has been 1st or 2nd team All Defense three times, Turner zero. George is regularly among the top 10 in steals, DRtg, and Defensive Win Shares. Turner has never finished in the top 20 in any of these, or any other, defensive category.
The good news is Turner's defense has been steadily improving. George's defense hasn't quite returned to the elite level he was at prior to his injury, but he is still a top 20 defender in the league.
BNM