I see what you are saying, but sequential manual boxes are so fast that this is almost a moot point now. An F430 will go from 6th to 2nd faster than you can say "6th to 2nd", perfectly rev matched and ready to go. At the most you might lose 2 tenths shifting the sequential box down, but you would gain back the 2 tenths going up to 3rd.
I wouldn't be surprised if the car is offered with a 6 speed manual and 7 speed sequential. For you drifting and trackday guys, if you want to take $80,000 or so of cutting edge sports car, tear all the electronics and 4 wheel drive out of it, go for it. I'm not as confident in my ability to handle this type of car without aids except on a wide open track.