The Spurs were actually one of the best teams at defending the p&r last year from a scoring perspective..they were 7th at defending the ball handler on the p&r, and 5th at defending the roll man..
However, I agree that they do allow too many open looks and relatively easy shots for the other team from a playmaking perspective, and I definitely agree about the perimeter D..the perimeter D is much more of a concern for me than the interior D is..
The Spurs' defense also suffers immensely when Blair is on the floor, just like last year..they were a few points worse with him on the floor last year, and it doesn't look like his D has improved..
The Spurs' 1 on 1 perimeter defense was 27th in the NBA last year, which is what made me concerned coming into the season..opponents penetrate against the Spurs' very easily, and the perimeter defenders are just poor overall, lacking ability to contest..
Other than the 1 on 1 D, their other weakness is defending screens, which is partly due to Duncan's lack of mobility when coming outside of the paint, and due to the fact that the perimeter defenders are poor at recognizing the other's teams offense..they're also too slow to recover..
George Hill was ranked as one of the worst 1 on 1 defenders in the NBA last year, opponents shot 52% against him..he was also ranked as one of the worst rotation defenders in the NBA as well..his p&r D was surprisingly his only asset last year..
Jefferson was very poor at defending the p&r last year, he was below average in the other facets..Manu was horrible at rotating last year, surprisingly, he was a good p&r defenders and decent at everything else..Parker was a mediocre p&r defender and decent at everything else..
Bogans was actually a really good p&r defender, but a horrible 1 on 1 defender and rotation defender..Malik Hairston was ranked as the only great 1 on 1 defender on the team last year..
Spurs' perimeter D is terrible, and that was my biggest concern coming into the season..they will have to hope that Splitter can make up for it, which is something I wouldn't count on..