Originally Posted by
Brett Skullcrack
You will not wipe at a progression encounter because sub is theoretically 5-10% behind another spec, you wipe because you don't have the correct tactic sorted and practiced. The theorycrafted dps difference is the last thing you should be worrying about, the only question that matters is "can we beat this boss with this raid?" And for sub rogues, the answer is "yes".
I would bring a dedicated sub rogue who has played the spec for a long time, knows that it's inferior in theory but still keeps pushing as hard as he can in raids, rather than a FTOM spec swapper. I want a diversified roster for the very same reason I want a diversified investment portfolio; you cannot predict what Blizzard will throw at you next in terms of spec nerfs/buffs, gear changes and fight mechanics. I don't want to rely on FOTM speccers who don't play any spec perfectly and instead rely on the relative tuning advantage for their performance, I want to know that if in T12 Blizzard puts out a boss where sub can make the fight substantially easier I have a dedicated sub rogue that I can call on.
It's not a special case, it has happened over, and over, and over again through the raid tiers to various specs and classes.