I'm not disputing that the two specs could be better, but generally it's more worth it to look at class versus spec. That's why warlocks are (generally) judged by affliction, mages by arcane, warriors by fury, and death knights by frost. As a DPS main for those four classes, you'd be expected to switch between your DPS specs.
Shamans are bad, I won't lie, and I agree that you can't really "expect" elemental players to switch between enhance (not saying that some won't switch), since that's ranged versus melee, which means the playstyle is very different.
I digress now, let me ask you a question: Where do you think affliction belongs on the pack, and how big of a nerf would you put in if you were the lead game designer?
P.S: On 25H spec score, fury warrior is 3rd, and frost DK is 5th, so warriors and death knights are 3rd and 5th on DPS, which is not bottom, but in the top half. Considering they are also hybrids with excellent (compared to other) tank specs, that makes the class as a whole place very well. Meanwhile warlock, and mage, and rogue off-specs are far lower ranking.