Hareem, for me it's the opposite. It really depends how much mastery vs multistrike you have on your gear.
Bloodbath can be only better than bladestorm, when your mortal strike and sudden death proc damage outscales bladestorms free rage input and the good burst it provides. Especially inside every 3rd colossus you should use bladestorm straight after CS (along with ravager) instead of standard dumping rotation. If you have a lot of crit and multistrike gear, bladestorm just wrecks bloodbath on every scenario I'm afraid.
Using 2 set from PvP and a lot of mastery gear can turn this around already with the current gear though, because if you can force charge crit mortal strikes on every bloodbath the value of the dot increases of course. Tier 17 sims stuff with a lot of mastery, which is the only reason why bloodbath is even "viable". It also emphasizes on using sudden death and it obviously kinda hopes you get those procs inside bloodbath too... While in reality - not gonna happen, so bladestorm burst still more reliable on stable damage done.
mrchee is also correct on the execute phase. It works perfectly there due to giving same pressure of damage between execute downtime dumps, while being completely free and giving rage with autoattacks. You basically have no downtime for two execute bursts in a row and perfectly executed it feels to be way better than bloodbath ticking there from one execute burst.
However this is old news and I'm suprised some people are still not informed o_O.