I think the way that hr727 was written up was pretty good in the way that it specified maximum power and then also expressed the maximum speed in terms of being solely under motor power. That encourages designs where human power is a significant component (unlike traditional mopeds with vestigial pedals), without falling into the trap of specifying a maximum operating speed. Remember, it's not hard to get a human powered bike over 30 on level ground and much more downhill. Recumbents, tandems, velomobiles, and fit riders on tribikes or road bikes all can do it easily. If you specify max speeds on ebikes though (without power qualifiers) you get weird situations where you could be operating them illegally even with the power system shut off completely. Look at this bill from Illinois, it starts with criteria based on HR727 (good), and then adds a goofy additional operating restriction of no more than 20mph on any street or road, making them slower to legally operate than regular bikes. I can get my Dash up above 20 with the power off even with the cogging fighting me. On the Haibikes I rode that had zero drag when not providing assistance, it was trivial.