They are in fact back. Grabbed one to try it out. No more buttons to activate the electric assist - hop on, pedal and the assist is instant on. It feels like the assist gives out somewhere around 12 to 15 mph if I had to guess. Coming off the Brooklyn Bridge the electric assist did not slow down the bike - you could spin out and gain speed if you wanted to. There are no gears to select - it is strictly single speed but it feels like they designed the combo - gearing plus assist - in a well thought out manner so starting from a stop is not difficult and the top end isn't so limited that you get frustrated. I tried as much as possible to pedal up to and past the point where the assist gives out. My commute took 18 minutes versus my normal 23 minutes average from near Atlantic Terminal over the Brooklyn Bridge to lower Manhattan. For reference I have made the same trip on a "normal" citibike in 18 minutes under perfect conditions going all out - perfect conditions being a properly adjusted Sturmey Archer, fully inflated tires, catching all the lights, in cool spring weather in shorts and a t-shirt. My route according to google maps is right at 3.4 miles.

Not sure I will use the e-bike version much as the bike commute is the extent of my exercise these days but it is a nice option to have.