In my defense, I was a crappy gamer when I played FFVII gonna have to infract myself for being off-topic
Yeah you can stack multiple of those. And it works pretty well for "high proc ratio builds" (CM Wiz as well).
Some of the proc effects are kinda meh compared to others, though. Chance to Slow, Chill or Immobilize for instance. Chance to Knockback also doesn't work on a lot of elites. Chance to Fear, Freeze or Stun are awesome, if you can get 4%+ on a good piece of gear, they're actually pretty powerful.
Actually I kind of disagree with the staying in the game through acts thing,
remember how annoying it was in D2 to join an ''act 1 andy'', or ''act 2 duriel'' game just to join party and see that people were in act 3?