It slows attack speed by 20% on bosses.

If you *Really* need the points, it's probably the best tanking talent to drop. The 20% swing speed reduction on bosses is pretty huge, but and any other tank can provide it, dps DK will keep perfect uptime on it, and dps shaman will have high-to-medium uptime on the debuff.

Depending on circumstances and raid comp, it might be a pretty good idea to drop it in favor of other talents, but if you're goal is to be a solid back-up for when things go FUBAR, every mitigation talent is worthwhile.

If you have a DK in your raid, it is unneeded as Frost Fever does that as a normal effect. Any of the specs should be able to keep it up, as Unholy does plenty of damage with diseases, Frost has Rime procs and Howling Blast, and Blood should keep it up as much as possible, as they're a tank, and 20% decreased attack speed is awesome for tanks and healer mana. If you don't, then it's fine to take it, but if you do have one in your regular raid group, I would say don't bother picking it up.