I wholeheartedly agree with you that suspension is a necessity, especially for 28MPH-capable S-pedelec ebikes. I've met a few people who are really happy with their rigid-frame bikes, though. Also, when I rode the Stromer ST2S (which has a rigid frame), it seemed that the geometry combined with the tire size and tire pressure seemed to help the ride quality quite a bit, and the bumps weren't jarring for my shoulders and back. I guess it's just personal preference.