I actually work in the commercial UAS industry; am actually somewhat of an expert, speak at conferences, advise industry clients, fly for profit, etc.
Amazon, Fed-Ex and many others are pushing the FAA for more access to the national airspace, to essentially, "file and fly". Recently the FAA divided UAS into a few categories, the small UAS defined as 55lbs and below that must fly 400Ft agl and below.
It is felt that the rules for flying small UAS in the National airspace (airframe certification, training, capabilities, etc.) will be defined and proscribed in 2015. That is why Amazon is pushing so hard, along with other industry folks: Unmanned large aircraft for package hauling.
I have been in the UAS industry for over 12 years, first in the military and now commercially: The capabilities of small UAS are astounding, both fixed and rotary wing. The fly with much greater accuracy than their manned counterparts, and I have a lot of hours flying.
There are many industries out there looking to replace manned aerial platforms with UAS...and they will.
Here is a good website for lots and lots of info:
Home - Association for Unmanned Vehicle Systems International