I have seen many posts aobut raid buffs saying that you need either an Elemental Shaman (
http://www.wowhead.com/?spell=57722) or Ret Paladin (
http://www.wowhead.com/?spell=20337) for the 3% crit debuff on bosses. Many people seem to forget that Assassination rogues (which pretty much every raid will have now due to the OP dps) can do that too.
http://www.wowhead.com/?spell=58410 says hi.
Kind of a QQ post, but there is really no need to make a point of having that, you will pretty much always have that up on a boss (If you don't, your Rogue needs to go reroll ASAP). If you want it on the adds too, sure go for a shammy for ToW, but single target, it isnt desperately needed.