Rend is both a TPS and DPS LOSS. It does less damage and less threat than any other ability you could do that requires a global cooldown (aka devastate, revenge, shield slam, shockwave, and even conq blow as far as threat goes).
Let me say this clearly so that there is no confusion on this...
As a tank... NEVER EVER EVER EVER EVER EVER EVER REND OR SPEC INTO IMP REND, EVER EVER.
"If the world is something you accept rather than interpret, then you're susceptible to the influence of charismatic idiots." -Neil deGrasee Tyson
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