I inferred that you supported the nerf due to the fact that the only reason to defend it is if you concur with the devs that it accomplishes something.
If your position is merely that it isn't worth being concerned about, well, more power to you I guess. I don't understand that view, given that the majority of tanking done by warriors is in heroics (just as with every tanking class), but hey. I just don't like being pointlessly nerfed.
If I were to defend it, I would do so on the grounds that I defended (and would still defend) the Imp Zerker Stance change: SBV is a disaster of a mechanic all around and anything that gets us away from it has at least some merit.
stuff
I have not Arena'ed since May. You are doing it wrong.
Gearing for Devastate/Cleave damage improves all the damage you do, including Shield Slam damage by proxy via crit rates, Armor Pen, and 2 STR - 1 SBV. Gearing for Shield Slam damage helps Shield Slam damage. The point of this nerf is not to nerf sustained Warrior PvE damage; it does not, and in fact it won't even affect warrior raid damage because nobody raids in block gear and the DR doesn't kick in until 2k block value, iirc. I have 1500, for comparison. It is solely for the purpose of nerfing five-digit SS crits from gear you would never wear in any real-world situation except Arena, where burst is king, much like the Prot Paladin nerfs.
As for damage relative to other tanks, iPaladins are OP, Druids wear dps gear to tank, and Warriors would be on par with DKs provided they were raid tanking with 2.6 speed 1-handers. The best damage buff Prot could see would be a change to HS mechanics but i don't know how you'd do that without fucking fury.
ps Warriors have poor AoE threat because they have the best AoE mitigation. I'm serious. We put AP and Aspd debuffs on an unlimited number of mobs in 2 GCDs.