Rend = Fail.....Are we so sure?
Shorty mentioned this and it has been a running joke for the warrior class since the beginning of time. Rend is the most useless skill in the game save for those odd PvP situations where you want to prevent a rogue from vanishing and getting the jump on you again.
Well, I was curious and bored and did some math.
164.5 Average Weapon Damage
1.7 Attack Speed
Using Rend Rank 9 (Rank 10 is available at level 76)
Formula as per the tooltip:
Rend - Spell - World of Warcraft
Yields an unbuffed damage output of 664.44
Divide by 5 (5 ticks over 15 seconds) = 132.88 per tick
Divide by 15 (seconds, duration of effect) = 44.30 DPS
Costs 7 Rage (10-3 for Focused Rage talent) so 6.33 DMG/Rage
This is on the weak side, using Mallet of the Tards in T5ish gear.
As per Satrina's Threat Values, Rend's threat is damage only.
So...first, off please point out any flaws seen in my math and/or assumptions.
Further assumptions being that it scales up with AP and weapon damage. Buffs like Kings (via STR) Might, Battleshout, etc will increase the output. The 35% added damage component is not considered above but being as how I witnessed ticks of 197 while out playing around with it means its plausible that my math is ballpark correct if I had a buff up (BS, most likely)
Also not considered: any debuffs added by other classes or talents in other warrior trees that augment the damage done by Rend.
Hypothosis: Rend can add a fair amount of damage and threat if used while tanking mobs that are likely to A.) be effected by it and B.) last long enought for the duration.