What's disappointing is that they advertised 20kw in the first place.
If you break down the specs, the battery on this is 230-250 18650 cells, likely Samsung 25R, probably 20s or 21. Assuming excellent pack construction and low termination resistance that's going to be something like ~30mohm IR, meaning that at a 200a discharge it's going to put out about 15.5kw. Today a 200a discharge is about the current limit on a controller of the physical footprint they're using. Even if they had some special sauce amazing controller capable of delivering the 270 battery amps required to hit 20kw on 72v nominal, the pack as implemented would be pushed to its limit. You either require substantially more cells (and weight/volume) or you need to move to a more power dense cell, compromising advertised energy capacity and range. So this bike was never realistically capable of 20kw from a battery/controller perspective. Not enough cells.
20kw into a motor with their dimensions is absolutely doable, but starting to get to the point where cooling becomes an issue, conductor size etc becomes substantial, bigger heavier controller becomes more difficult to package etc. From their comments on facebook it appears that they had rated the bike based on what the motor was capable of running, not what they were actually feeding it at any point.
All that being said, they are absolutely correct when they say 15kw is plenty. Given gearing is probably for ~60km/h with field weakening to extend the top speed to the rated 80km/h, stator size and rough KV given the size of the pulleys it should be able to rip wheelies on command. You would really struggle to load up a 50kg bike to get above 15kw unless in sand or snow or you were really, really fat. As somebody who has a 50kg bike with a 200a controller and 240 18650's, it's plenty of power.
I really like all of their engineering choices. It's eerily similar in many specs to what I ended up building for myself. The design with trellis frame, single pivot swing arm with pivot mounted hub derived motor is very close to drawings I did a couple of years ago too. I would absolutely purchase one of these and ride it on the street, if they were actually available. I love the product engineering, but the business decisions and priorities are questionable at best IMO and any excuses around multi year delays are difficult to accept.