To put it in perspective..
There were estimates that 1,000,000 consoles were pre-ordered.. Taking that number and not any unreserved units available at launch... .04% of 'defective' units represents only 400 units.
400 units of 1,000,000. That is pretty great.
That problem is that the internet is a great place for these issues to fester and drown out the million+ good units out there. People search for reviews, and find bad reviews and problem reports placed more prominently. Why? Simple.. because what incentive do the 1,000,000 happy users have to go talk about it on the interweb? The majority of people who have a negative experience with a product will plaster it all over the place.
I could be wrong, but on electronics isn't an acceptable 'defective' rate around 1%?
And I think we can agree that things like a missing controller, missing HDMI cable, etc.. doesn't fall under defective.. That's more a packaging issue.. And units that arrive damaged are probably a result of being damaged in transit from the manufacturer to end-user. Defective would mean a faulty switch, disk reader that doesn't read, etc...