The movement capability was more meant for PvP, and the fact that a class already lacking gap closers shouldn't have to stop moving to use a finisher and lose ground on it's target... If you use it on a PvE mob that is running away faster than you can run, and it breaks before it's finished because it got out of range, that's your own damn fault.
I think the reason I don't like the vacuum is because it would lack the selfhealing survivability that Ret badly needs right now, which is why I tried to rework the ability within it's current purpose, healing and damaging equal amounts to the paladin and their target.vacuum