Interesting thoughts. I've never really thought about it myself, but it does appear that Nintendo have become insular and predominantly support their home devs.
I suspect Iwata is a strong micro-manager, as this isn't the first time I've heard about NOA not having the level of autonomy you'd expect from a company of Nintendo's size. This of course means he's great at getting deals with Eastern devs, but is weak in dealing with Western devs, but being a micro-manager won't trust his staff in the West to do their jobs properly.