Dual core and CMT are huge features, and it would be very a major FU if the chip was doomed because much less important feature such as Foxtron.
I fully agree that not being able to gracefully disable a technically innovative but risky feature like Foxton was a major ****up. It was also easily avoidable had someone asked the right question a few years ago. The fix is relatively low risk but a big schedule hit is unavoidable. IMO some heads should roll.