Adding more power would not be a bad thing but I think going beyond this amount of power by a significant amount will cause more issues. Standard chain/cassette/derailleur systems are at the limit with current power in terms of reliability.
This is exactly my thought.
If Bosch were to make a 500W motor based on the Gen 4 platform, that would be fantastic! Even then, it would require heavy duty components.
But once we start hitting 750W+ as in the case of Ultra, the dynamics changes. It necessitates super heavy duty chain or belt, much tougher cassette and free-hub body, chainring etc.
Most bike parts are not made to withstand 750W of continuous power!
I have seen lots of riders with Bosch motor cross 15,000 miles and they do go through lots of chains/cassettes.
I can't imagine how many chains and cassettes would be needed in the case of Bafang ultra with 15,000 miles on it. I wonder if there are any riders with more than 15,000+ miles on their bike with the ultra motor. That would provide a good point of reference.
Bafang makes hundreds of thousands of hub motors, perhaps one of the
highest volume hub motor makers in Asia but their mid-drive motor production volume is very small compared to their main bread and butter hub motors.
For those who are interested, they can see
mid-drive assembly line in this video. Looks like a small-scale operation and this was in 2019 and I am sure they have expanded it to include the M500 and M600 motors.
From what I can tell, they are limited by their access to high quality sensors and electronics, perhaps mostly because of patent licensing fees!
if Bafang can offer higher quality mid-drive motor with higher reliability and quality control, they may succeed in competing against Bosch and Shimano drives and that will be a good thing. But, right now, it is not even a comparison in terms of quality or volume. The volumes of Bosch motor is almost 100x compared to Bafang mid-drive systems.