Sure - this might be a good example here because any rules the FAA will come out with in this regard will probably require you to be able to read a sectional chart unless you're really in the middle of nowhere. The DJI drones are all easily capable of altitudes that could interfere with VFR traffic and in places like the Bay Area the ceilings people are flying under are often quite low to avoid, for example, the SFO airspace. Drones are way more maneuverable than airplanes, so the realistic burden will be on the drone operators to avoid rather than the other way around.
Definitely shouldn't be a two-years-of-flight-school thing, but there probably is a written test at the DMV somewhere in here.
It doesn't hurt to lose a $300-$1000 quadrotor pilot license.
It might start out as a 10" wide quadcopter, until the first major crash. Instead of ordering a new arm, it can be reconfigured as a tricopter with the addition of a servo. After a while, the tricopter might become a V-Tail if the user likes the flight characteristics.
Then FPV kit might get added, or a GPS reciever. Now it's flying semi-autonomously and the user wants better quality video, so it's transplanted onto a 18" frame, fitted with a gimbal and nicer camera.
At what point does the multicopter need to change registration numbers?
A simple "You must have your name and contact info on it" rule would be more than sufficient - and in fact is already the case for 90% of the aircraft out there. I even have my contact info taped to the body of my little 4" Hubsan quadcopter; I'll probably never need it, but why throw away expensive hardware if you don't have to?
I think that there are a couple of obvious rules that could be applied to speed things along: 1) limit location and altitude of flying, 2) require hands-on control (or take over), 3) require line of sight, 4) enforce some reasonable weight restrictions (for cameras). If you could meet those four things, then I don't see why you'd need to have a commercial restriction. You might have other issues to deal with for insurance, but I don't see why the FAA should care about commercial/non-commercial with such small craft.
Now, when you get into autonomous flight and real payloads, then that's a whole other ballgame, where I think the FAA will have some real work to do. In particular though, I'd hate to see them limit the hobbyist segment too much. I think it would be a lot of fun to build a small, autonomous drone that could fly using GPS waypoints with a camera. I just don't want to have to go through 2 years of certification to be able to fly it!