The new 20 inch bike I am building will, indeed, use a radical new motor, but not the 4 inch Astro. There are a number of reasons for that. I will get deeper into that on a later thread.
Anyway, I am very focussed on small bike builds. I like the compact design for loading into a trunk, the lighter weight, and the additional strength afforded by the smaller wheels (large wheels tend to be weaker and give more load to the frame). Gear ratio is also easier to deal with for smaller wheels. Also, the fun factor is high on small bikes for bashing around town.
1% of the world's population can think "Outside the box". The rest are firmly stuck within the box. Where are you?