No doubt the armchair aerodynamicists can find a multitude of things wrong with Peter Sripol's electric biplane, but it certainly does fly.
The 105kg English Electric Wren flew (just) in 1921 on 7.5hp, so, after 96 years and with the benefit of modern materials, it should be possible to build something considerably lighter.
With the ready availability of large brushless motors, speed controllers and lithium polymer batteries, and the sub-70kg category needing no regulation, we are likely to be seeing more designs like Peter Sripol's biplane. The lack of the most destructive vibration that small high powered engines produce and the ease of multi-electric motor installations opens up a multitude of new avenues to designers.