I personally love the idea behind this. I think it needs some changes to be sure but a chance to reduce the cooldown is always a plus for me. I think what gets most players about this is the low chance.
No that's not the problem.

This skill doesn't really play in favor of the SCH that want to use specific skills at specific times. But the way this trait is designed favor using stacks as early as possible to have a (absurdly low) chance to get the most of it.
And what you get is a key cooldown of your gameplay being up at more and more random moment the longer you're fighting.

You can't plan on RNG, and SCH need to know what kind of resource it will have at what kind of time. Counting on procs is a very unhealthy way to play the job.