This sounds good in theory but there are a TON of variables that would be really hard to encapsulate. I'm not saying it can't be done, but (good) defense in basketball is extremely team-oriented. Positioning, rotations, double teams (and the rotations that accompany them), etc., not to mention zone defense.
To give a more concrete example, a team with a great defensive center gives the guards flexibility to play tighter man to man, because they can more readily afford to let the guy they're guarding get by them (thanks to their "backup", the center). This has the additional consequence of implying that they give up less room on jump shots.
Another thing to consider is steals. A steal is really big because it obviously prevents the opponent from scoring, and frequently leads to fast break opportunities. However, it's misleading to simply look at the number of steals a player gets. Some players get steals within the "flow of the game", whereas others get them through gambling (I don't have a quantitative source for this, but anyone who's watched Larry Hughes play knows what I'm talking about) for steals, meaning that whenever they fail to get the steal, they also end up way out of position, often leading to an easy score for the opponent.
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This sounds good in theory but there are a TON of variables that would be really hard to encapsulate. I'm not saying it can't be done, but (good) defense in basketball is extremely team-oriented. Positioning, rotations, double teams (and the rotations that accompany them), etc., not to mention zone defense.
To give a more concrete example, a team with a great defensive center gives the guards flexibility to play tighter man to man, because they can more readily afford to let the guy they're guarding get by them (thanks to their "backup", the center). This has the additional consequence of implying that they give up less room on jump shots.
Another thing to consider is steals. A steal is really big because it obviously prevents the opponent from scoring, and frequently leads to fast break opportunities. However, it's misleading to simply look at the number of steals a player gets. Some players get steals within the "flow of the game", whereas others get them through gambling (I don't have a quantitative source for this, but anyone who's watched Larry Hughes play knows what I'm talking about) for steals, meaning that whenever they fail to get the steal, they also end up way out of position, often leading to an easy score for the opponent.
The list of variables goes on and on....