Haste and holding aggro with procs

[Nirgon]

70% slow do the math

[Feanoir]

If I understand how proc rates work, and I may not, rates are adjust per swing to give the same proc/min regardless. If your proc rate is say 1per 50 swings unhasted, and you have 100% haste(just for ease of math) your proc rate will drop to one per 100 swings. Say you have 50% slow it will bump up to one per 25 swings. Haste/slow only adjust proc rates per swing to maintain same proc/min ratio.