i'm pretty sure I had to spec into that on my watchman.
for the other guy...
a mezz after a leap?
the guardian tanks have something more frustrating where they gain cc immunity after their leap.
the root after leap is specific to combat spec and goes along with master strike. it's core to that spec, and there are a lot of ways to circumvent it anyway.
Leap roots and interrupts in any spec. Watchman spec gets Zero minimum range Leap, which acts like an extra melee interrupt/root. Some specs like combat and Vigilance can spec for an extra second of root to help them get Master Strike off.
I'm honestly a little surprised at your inaccuracy about this.