I love when people claim non-sense like that.
90k is absolutely unreasonable in 496 timeless gear and you won't really get a weapon over 450-476 before raiding LFR.
Also it depends on the class, I can guarantee you that a rogue in 496 timeless gear and 450 daggers is not even going to come close to 90k dps, try 40-60k dps.
Even when you are fully lfr equipped with some flex pieces you top out theoretically at around 150-180k dps and heroic raiders still do twice as much easily.
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sure when you figure in that ICC raiders pulled that dps with a 30% or so static progression buff in ICC.
Also 2k dps is BAD even when you just hit 90 in WotLK. If memory serves me right I played a retribution paladin at the end of bc and cleared sunwell with my guild and top dps in sunwell was around 3-4k dps (I think) and I don't think when we cleared naxx, malygos heroic, sartharion heroic in week 1 of WotlK and still in t6 that people were doing only 2k dps.
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I don't have anymore vanilla logs but I am sure as hell that you are wrong about warriors doing 1k dps and dungeon set rogues for example doing 200 dps.
To give you an example ok, I was a hunter in the EU 2nd or 3rd Loatheb kill. I had leveled that hunter a few weeks before on that server before I switched to the guild. I basically had 4 t2 pieces and the quest bow but I ranked higher on the dps meter than the other 2 hunters who had better gear and I was like 8th in dmg in a 40 player raid.
That would be impossible right now with the difference gear makes.