From what I've read about Bethesda's "parity of performance" it seems like they will go out of their way to make sure the game looks the same on every platform, even if one of the platforms has several times the computing power of the other two. Why? Is it to "be fair" to owners of technologically inferior platforms? Battlefield 3 isn't going to be fair to them.The Witcher 2 isn't going to be fair (if it does get ported). CoD4 (MW1 ... not 2) wasn't fair. Battlefield: BC2 wasn't fair. Your own games are horribly unfair in this regard due to construction sets. Why try to be fair when it comes to visuals / gameplay if you're going to support modding? Is it because you are too lazy to implement proper support for DirectX11 / current PC hardware? You just don't want to? Why is it acceptable for your game to look like a PC exclusive from 2006, and have noticeably worse visuals than a PC exclusive from 2008 (Crysis)?
tl;dr: Justify "parity of performance" to me, because it sounds like an excuse.