This was overdue as well. But they shouldn't have put an internal CD on it. Where anet fucked up was this would give a stacking timer on the stealth granted, rather than refresh the timer on stealth. So if you fell 3-4 times in succession, you'd have like 15 seconds of stealth instead of 3-4 seconds.
I think every other "X happens when you fall" trait has a cooldown.