Agree with all of this. From my experience playing I love guys that gamble for steals... they get you every now and again but 9/10 they end up out of position. Guys that are disciplined make things much harder.
Perimeter length makes ball handlers uncomfortable and uses up portions of passing lanes... makes everything harder. Length on the perimeter is very important.
I think the main responsibility of a perimeter defender is staying between his man and the basket, which also means not losing him on screams. Thus, he has to be athletic (or at least "mobile") and have great defensive awareness. If, besides those qualities, he also happens to have a long
WINGSPAN, that's a bonus which may allow him to
ALSO disrupt passes and get some steals. The interior defender job, I think, is very different: he doesn't have to run around as much, since to stay between his man and the basket means covering less ground, but he is asked to challenge shots much more often than a perimeter defender. A perimeter defender can make half-hearted attempts to block shots since he is not expected to really block them - as he is usually somewhat far from his man. The inside defender, on the other hand,
HAS TO chalenge most shots because close shots are easy to make. His main job is to protect the rim, to chalenge anyone attempting from close range. That means his
STANDING REACH plays a bigger part on his effectiveness as a defender than the
WINGSPAN plays on the perimeter defender effectiveness. In other words: it is very hard for a short-armed player to be a very good interior defender, whilst is a lot less problematic to a perimeter player to have short arms.