Sounds like your problem was the occasional tire/rim combination that is a tight fit and (AFAIK since I've seen others with the problem on non-e's), not associated with electrics only. You must have a of hub system since my and friend's mid-drives (OEM & DIY) use QR's. I had a flat on my Haibike once and repair was the same as any other bike with the exception of being heavier to invert.