While I haven't seen an official statement regarding attack speed, I'm assuming that the speed statement on a weapon works just like the attack delay for units in Warcraft 3, which is to say that it is a polled delay (based on a game-internal timer on the server, not the server's system clock). Basically, the server drops a wait command for that length into the queue before it runs your attack routine again. This is why, when the server is slow, everybody attacks slower. When your connection is slow... You die. ^_^
Regardless of how the timers are set up, the supplied values work out with the proposed algorithm:
((WeaponDamageMax - ((WeaponDamageMax - WeaponDamageMin) / 2)) / WeaponDelay) = DPS
to wit:
((84 - ((84 - 55) / 2)) / 3.2) = 21.7
If we assume that the proc fires 20% of the time (which would be awesome, it's probably more like 5%), the proc would still only add ((ProcDamage / ProcLength) * ProcFrequency) damage per second, or:
((100 / 30) * .2) = .67
So the proc isn't exactly earth-shattering, but procs aren't supposed to be. They are a nice bonus when they happen, not something I count on... ^_^
EDIT: Parenthesis correction.
Edited, Wed Jan 12 15:10:07 2005 by Aelfraed