To me advanced statistics won't be worth anything until they can measure a big man's defensive impact accordingly:
shots adjusted, passes deflected/intercepted, blocks and pockets picked on both perimeter/frontcourt players, points allowed through mis-rotation or being directly scored upon, how many times he's in isolation either in the post or perimeter, how many times he effectively plays help defense + the # of different attackers in one play he limits, how many times he has to deal with funneled attackers, how many times he has to deal with his man + stunt'n and helpin on teammate's man, how many times his hedging allows his teammate to recover, how many times he's successful at breaking up/guarding pick and rolls, how many times he closes out on pick and pops, how many times he forces players to a bad spot on the floor, how many times he boxes out offensive players when in the paint, how many times he aids defenders, how many times his direct opposite scores on him, how many times he shrinks space in the paint, how many times he traps perimeter players, how many times he forces the attacker into a bad decision, how many times he's inactive on the defensive end etc etc.
And they find a formula that can accurately calculate all that into an individual performance-stat for that player.