Blizzard have posted a new developer journal explaining imminent changes to how Crowd Control work in Diablo 3.
The developers go into minute detail at the journal, but the general thrust is the following:
Monsters have a "CC resistance" that is stored on a per-monster basis.
The CC resistance starts at 0%. For every 1 second CC that is applied to the monster, the monster receives 10% CC resistance.
Monsters lose 10% of their CC resistance every second that they are not CC'd.
Elite monster CC resistance is capped at the current reduction values already active for Elites. In other words, CC resistance on most Elite monsters is capped to:
35% in Normal
50% in Nightmare
65% in Hell
65% in Inferno
