I agree that the combat tree could use some work and there are definite PvP talents at the bottom but murder spree isn't only a pvp talent. You don't have to ping pong from target to target. "Can hit the same target multiple times." Imagine you are on a raid boss. So you trinket up, equip a slow off hand hit murder spree. You basically stormstrike every half second for 5 seconds. Then you reequip your fast OH and go about your business.

Honestly though it isn't stellar, and it is useless on trash where everything is CC'd but one target at a time. I know blizz is trying to make all trees viable for everything but rogues generally acknowledge that combat is our PvE tree and sub and assassination are the PvP trees depending on your tastes. I wish Blizz would give us only PvP talents in combat.

One a side note, Sub looks great until shadow dance gets nerfed. Waylay and the other associated talents finally bring ambush/dagger rogues back in a big way. We'll have to see if its viable (I'm not in beta) but it looks fun.