Came back to PvP this season since whatever the last season in Cata was.
Shocked to see they still haven't fixed Dispersion. The tooltip states "Clears all snare and movement impairing effects when cast, and makes you immune to them while dispersed."
It clears stuff on you when cast, but it sure doesn't make you immune to them after the cast. You still get all kinds of Slowed, Trapped, Gripped... you name it and it's on you.
Really poor since this is Shadow's only real escape mechanism -- and it doesn't allow you to escape. And no, I don't play Disc so you can leave those suggestions out.