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Recumelectric: You're absolutely right. 800W is more than enough power. I often use the 250W setting while riding around town (n.b. the controller still provides high power when accelerating under this setting). What is 800W good for? Quick acceleration while riding in traffic is the big one. Also ridiculous hill climbs become possible. Yesterday I rode up a steep access road in the mountains - 1700' of elevation gain in 4 miles - in 25 minutes. That's about 1/3 the time it takes stronger riders than me. Going up sucked about twice the normal power (8.8 amp-hours). Going down overheated the brakes!

bdcain: Letting go of the throttle when shifting seems obvious to me - mostly to reduce gear wear but it mostly eliminates your concern as well. I suppose you could still hit something with the derailleur and end up out of luck. For what its worth, there is a beefy milled plastic chainguard which should keep the chain on the (single) front gear. The use of a single front chainwheel makes the rear derailleur's job that much easier. Overall I see the risk as lower than on my mountain bike.