Assuming you mean in PvP, its not a big deal, leaps cooldown is 15 seconds, meaning unless Zen Strike procs for you, you're going to be using leap again before your 2nd Master Strike anyways, OR you can use Force Push to get another leap in as well.
And if you take Preparation for PvP (which you should), you'll have everything off cooldown everytime you finish off a target anyways, fantastic if you're picking off a ranged DPS in the back who isn't being supported by his teammates.
Preparation only works (If I read it right) when combat drops, not when you get a kill. If it was when we got a kill we could just use combat focus and spam slash and kill mobs and rinse and repeat lol. Dropping combat is difficult in large group based pvp,
I foresee it's use to set up huttball chains if people kill those targets individually,
or if you know