I wouldn't mean for a certification pathway for UAV operators to exclude autonomous operation, but it's certainly a harder problem. It will probably be similar to current aircraft certification. Small companies have long histories of building and certifying airframes, so I don't buy your argument that it would "seriously stunt" drones. A company that can raise money can go through airframe and type certification. The costs come down in proportion to airframe fabrication and fuel costs.
It's one thing to let cities set their own rules for local flights below 400 ft. What happens when a software bug sends you up to 1,000 ft? Accidentally busts Class B airspace? These are similar issues as being seen with autonomous cars and can't be easily waved away.
The problem is that while legislators and rule-makers often react quickly when restricting things, they are very loath to repeal restrictions. A work-around is to permit most things by default, then restrict in reaction to specific issues.
Two excellent examples of squandered potential are general aviation and amateur radio. Both have been encumbered by nationwide rules that quickly became outdated. (Seriously, Morse code?) I'm very worried the FAA will do the same to drones. After all, that's what they're incentivized to do. They only get fired when someone is killed by a new technology. They aren't commended when millions benefit from it.
On the other hand, the FAA could drastically accelerate drone development with one simple rule: Allow cities and states to make their own laws regarding anything less than 10kg flying under 400ft. This includes commercial use.[1]
That's it. If local governments want to experiment, let them.
1. Of course there would be the normal restrictions around airports, military bases, etc. Also, temporary restrictions for VIPs such as the president make sense.
Automated drones would completely change how we live our lives. In contrast, the general aviation community is small and hasn't advanced significantly since the 1950's. The popular engines and airframes are almost the same as they were a half-century ago. Heck, most private planes still run on leaded gasoline. Restricting drones to preserve private planes makes about as much sense as restricting automobiles to preserve horseback riding.