While I think Juhanoh is being a bit sophmoric at best, I will say that if you take the literal meaning of his post title, then I would agree.
Shadow priests are GOOD at dps, they are not great. Chrizwan, please link footage of your "pwnage" of a raid as top dps. Back before TBC, I would have aggreed that given the opportunity and due to mana efficiency, a SP could potentially be in the top 3. Now, in today's BC world, there is little chance. If you read the boards, or follow any sort of spreadsheet data, you would also understand that we are + damaged capped for many of our spells and do not receive the full bonus of + damage on any of our nukes or standard spells.
Plus, in 2.4, resilience now effects a spell like mana burn, which in turn reduces our effectiveness in PvP. Think and study before responding a bit more. I will say that you did take the time to mention spell rotation, dropping the use of VE and VT, and so forth which are all good points if you want to be up near the top. As it stands, if the damage meter is all you care about, then a Rogue, Mage, or Warlock should often own most of the top spots and Shadow Priests own the upper middle with tons of utility. I still love Shadow Priets, just wish they would fix them a bit more.