That NIE was strategically positioned by the DDI who is a career bureascrat wishing to make a name for himself. It was based on a single defector to a foreign intelligence service. To play politics with a possible threat to the US is treasonous at best.
A good question to ask is why would they continue to work on Long range ICBMs but discontinue work on thier nuclear weapons program. Why would they also be enriching uranium to a point well beyond what is most efficient for reactor operation? This also contradicts the previous 4 NIE's, so the intelligence was either bad then, or is bad now.