If the approach is to take observations and then dig into as much statistical evidence as possible, including those that vary from initial conclusions, then I have no problem. That's good stuff. But look at stats first, assume some kind of meaning such as elite qualities being exhibited, and then offer anecdotal suggestions to back that up, and I won't be impressed.
Consider the anecdotal evidence regarding the harder covers. Funny, but I can recall far too many times when he switched off those guys, or when he would be assigned Ben Wallace and still get torched.
It isn't hard to just express what is seen and clearly visible from game to game. Every off-season we see stats and memory-based observations that imply that he is "impressive" and the problems originate with Jose Calderon
and Sam Mitchell. Whatever. Javale McGee has impressive aspects to his defensive game. Jose Calderon
does some impressive things defensively. Boris Diaw looked pretty nice next to Chandler. When Bargnani
can consistently do things that help to create stops against offenses of some complexity then I will stop being cynical. Otherwise I think there is a ceiling that this team will not break through, unless the team as a whole can take on those responsibilities effectively. There's no doubt he's shown improvement and is playing basketball on both ends like never before. Now I just need to see that consistently, and see where he fits in a scheme that can be relied on beyond the fodder teams.
Ultimately, I don't see where stats offer a great basis for defining defensive effectiveness. They can point to ineffective results, but even there you will have excuses. Basketball is a fluid game. If it was just about two guys matching up in the post like Olympic wrestlers, then I could see where percentiles regarding man to man defense would mean something. Instead you have a ton of team aspects that need to be accounted for, even with regard to man on man situations (how often does he need help or get help; how often does he switch off and why). Last season I saw him functioning on the defensive end from the start to the finish of possessions enough to make me really take notice. But when he was less than 100 percent that pretty much stopped. There's hope, but there is still nothing conclusive in my mind.