You have to understand that there are only so many ways of doing things efficiently, and then you're just into form over function.
If you consider the limitations of small aircraft (price, engine power, materials, and builder time/energy/skill), then it's clear that there isn't nearly as much room for NEW good ideas any more. The the ideas that best fit the above limitations have been done.
If you want to make a big leap forward, you'd need to go to a different airframe concept -- something like the blended wing body (see: www.wingco.com).
Proof of this is seen in military aviation, where budget, materials, and engine power are much less of an obstacle, bute even here we see the same basic designs with only minor incremental improvements. The innovations are found in things like avionics/radar and low observabilities technology.
BTW -- Burt is still here. It's not for a lack of innovators -- he's moved on to space flight vs. light aviation.