I ride our bike-share e-bikes for commuting all the time. They're awesome. I can ride 4 miles in 15-20 minutes during the middle of the summer through the center of the city and not break a sweat.
I don't really see a problem with e-bikes being used on MUP's, and we have plenty of them around here. Obviously if someone is riding way too fast for the situation or conditions, that's a problem, but that problem isn't exclusive to e-bikes.