Well, if power restriction and assistance were removed, it would be insane. I once built a "way too powerful to be useful" eBike that would easily hit 50 Km/h (About 30-something MPH). The thing was totally illegal and I did it just for fun.

Do you really want a 100lbs, 50 km/h eBike zipping around the bike trails? I don't think so. I for one like the 20 MPH limit on assistance. But I don't agree with the 750W rating. Suppose you build a trike for fat people and install an assist system to gradually help them get back in shape. 750W is going to have a hard time hauling their 300+ LBS up a hill.