Well I feel dumber for having read this thread. Just to throw my 2 cents into this pit, I ride a gen2 Bosch Speed motor which was marketed as 350w nominal. Yet it's clearly not the strongest motor in Bosch's lineup.
My bike is fairly heavy, I'm fairly light, and the motor is comparatively weak but it still puts a smile on my face on the ride home after a long day at work.
If you gave me a choice of 50% more motor watts, 50% more leg power, or 50% lighter bike the stronger motor would be a distant third.