No, it does not work with the Luftekappe. There is not enough room for them both to fit. I believe that Vorsprung has pretty close to the same ideal spring rate, we literally just approached it from different ends.
"Should" sounds a little absolute and I don't think that's correct. However, I'm only 5'7" and riding a medium Pole Evolink 150 where the reach is 480. I'm also running a 31mm stem and a forward saddle and it doesn't feel too long at all. The new Geo is amazing!
With the new oneup coming in at $199, $250 with remote and the most drop to overall length out there I don't see how people can continue to charge $350+ for a dropper.