Like you said I think they are overkill or WOW if that's all you're going to be playing, Now if you're going to be feathering some Crysis, COD: Black OP's or Battlefield 2 then yea you're right there where you need to be video card is lacking SLI or sorry Crossfire since they are ATI.
But yea for WOW and only WOW overkill.
Buy a good HP or Dell Desk top with 4 GB of ram an i7 or i5 processor and save about 700.00 if all you're going to be doing is playing WOW..