You know what Bloodlust does and you kind of have an idea by now that this is one of the more important reasons you are brought to a raid.
In case you missed it, the tooltip says that:
Bloodlust: Increases melee, ranged, and spell casting speed by 30% for all party and raid members. Lasts 40 sec. After the completion of this effect, those affected will become Sated and unable to benefit from Bloodlust again for 10 min.
You are no doubt familiar with the offensive uses of the ability and if you made it through any Dungeon, Raid or HC Dungeon you know when to pop it. In ICC it’s a little trickier, because, if you run with different Raid Leaders, they might have different approaches to its use. Take for instance the Saurfang the Younger fight, the last one in the Lower Spire. While I found that the best time to use it is when the dude’s HP is at 30% and he hits the soft enrage there, in PuGging the 25 man version I was asked to use it in the beginning (perhaps this way you guarantee a very good start for the team and manage to DPS more until the first Blood Beasts come out) and even have been asked to delay it until 28%. The latter is for situations when you need max DPS on the boss if a healer has the Mark or something and you want to burn the beasts down and thus get more face to face time with Saurfang under the effects of BL.
You will want to ask, if you are the only shaman in the group, or if you are the one designated to BL, beforehand, who will be the one that will give the go ahead (usually the Raid Leader) or if you can use it when you think it’s necessary. Enough of the offensive uses for it, tho.
Defensively it is a very, very powerful tool to have as well. Picture a fight that has heavy unavoidable damage on the MT and then a bunch of avoidable damage, such as Rotface. If one healer bites it fast, and by fast I mean around 70% and no Combat Rezzes are available (druid healer is the one that has been ‘deaded’ or the only durid you have is the MT) and it’s close to raid time end you (or actually the RL, if he is on the ball) might consider trying to go on and not request a wipe and a fresh start. A defensive Bloodlust will be the difference between a wipe and a kill. Pay close attention to the healer still standing and if it’s you, well, good luck!
Timing the BL just as the healer is getting overwhelmed is essential. The 30% haste will give him the much needed breathing room for upping the tank to full and then moving on to the DPS that need it the most. He will be performing triage at this point so if you end up being the one dying just Ankh up and keep on rolling. But, if a similar situation to the above one does happen, you have to be available to BL or else it’s pointless after all.
Another fight that has the same approximate mechanics but is far less punishing IMO is the Onyxia fight and the above can be used with the same results. Or Patchwerk, if you get the weekly quest to kill him dead.
I’m not saying that this is a good tactic to try but I did want to point to the spell being far more useful and, dare I say it, versatile, than usually meets the eye.
The PvP ramifications are all there, of course, but due to my limited time in Arenas, I would not dare venture in trying to give tips and pointers of BL uses.