The throttle is nowhere near as powerful as with the pedal assist and I really can't think of a situation where I need or want it. I don't think it's unrestricted but I'm not positive - I base that on the fact that lvl 3 and up feels much more powerful than the throttle. I'd just rather be pedaling than sitting there using a throttle.
The Magura brakes cut the motor as soon as they're pressed at all so the torque sensor doesn't come into play when stopping with brakes. You just get used to the timing of the motor cutting and coming back to power with stopping and starting. Same with getting into the right gear with the Kindernay. After a day or two of riding you intuitively remember which thumb shifter shifts up and down and know whether you were in a "good" gear or not when coming to a stop quickly and pick close to the right as soon as you stop or prepare to move again. When you're riding a motorcycle or driving a stick shift, you don't think in your head "I'm in gear 4" and when you stop or slow down "I was in gear 4 so I should shift to gear 2 to get up this hill" you just shift seamlessly to the correct gear based on feel and getting used to the bike/car.
We'll see about leaking no issues so far. Yes, shipping would be a big pain.
You really aren't pedaling fast to get to the high 20s or 30mph, it's more the effort. Level 1 or 2 will require more effort. Once you hit the speed "wall" with a given level and your own pedaling effort, you can click up to lvl 3 or 4, the motor gives more power and will push you to a slightly higher speed and with the same effort your pedal cadence will go up as well. Not having spent a ton of time yet riding, but cruising in the low to mid-30s probably feels a tad fast for sustained pedal cadence, but realistically if you are off-road or in any sort of urban environment you will not be cruising at 35 mph indefinitely.
I'd liken the shifting experience much more to a motorcyle with the kindernay. You don't have to worry about downshifting which is great, you can get into any gear at a stop, you ease off power while shifting and you learn to keep the motor and gears in a good power band to get around. Starting from a dead stop you run through the gears quickly but while the 7 speed kindernay might have slightly taller gears, I still think it's better to have more gear options across more situations than less shifting because most of your time spent shifting is adjusting a few gears up or down while in motion.
