If they kept the chance the same, but let new stacks refresh the countdown, it could be quite good. Then you're not guaranteed to get a full stack, you still have to get a bit lucky with procs, but once you hit a full stack, you'd get a good use out of it.
New stacks do refresh the cooldown.
RedShirt / Roleplayer of Giant Slayers, Inc. on Thelanis, formerly Tharashk.
Member of the DDO Player Council