I don't agree, amd has a major advantage over nvidia right now. but as we have all seen recently, all it takes is one decent card to change people's perception. amd can't afford to wait another year before rolling out SI or NI. I think they're smart to bump SI up to 400mm2 or so and release asap. they can always do the die shrink in 6-9 months, plus it will give them an excuse to come out with 7 series then.
edit: also, they will probably want to start 28nm with smaller gpus, especially since it will be gf's first go-round on gpus.