There's no denying the 5800k/7660D is a cheap, smart and efficient option for Sony. Also no doubt it's much more powerful than the GPU in the PS3, which I believe is some kind of cut-down nvidia 7800.
That said, it's not nearly as powerful as having a dedicated GPU in there. Last I saw, rumors were flying that the PS4 was packing a Sea Islands dedicated GPU, which would make it a formidable machine.
I just don't want to see them put in weak-ish hardware and have a situation 7 years from now where they stretch out the generation far longer than the hardware can cope with. Though I will admit that devs have done some amazing stuff with the hardware they're stuck with. Uncharted 3, God of War 3, Halo 4, etc.
Corsair Obsidian 250D - Asus Maximus VI Impact - Intel Core i5 4670k - Radeon R9 290