That's the thing about E-bikes, everything is entirely subjective. Throttle-boost is a MUST in my book, so that eliminates all the Bosch & Yamaha mid-drives. Torque sensor vs. other... I totaling prefer the Bafang style that adds power up to a speed, then backs off and lets you pedal; very efficient. Speaking of Bafang mid-drives, they can go from bike to bike AND don't use a proprietary battery; HUGE positives in my book too. As for tire sizes, I've never heard anyone state smaller wheels are more stable. Is that a mis-type? 29er's give the best roll and stability, combined with slacker head tube angles.

Unfortunately the pre-made's still have a long way to go, but the Shimano E8000 mid-drive does look promising when compared to the Bosch & Yamaha mid-drives. I think it will be better than both of those.

Like I said, everything in E-bikes is subjective. That includes what you get for the price you pay. Rohloff? Wonderful IGH, but cost more than most peoples entire complete E-bike!