Imagine the complexity of 12 engines, with all those moving parts, lubrication and cooling systems. At least motors only have one moving part, supported by a couple of bearings. Plus they’re easily kept coordinated electrically. Easy peasy.
Has anyone considered that, with a motor, aerobraking actually recovers energy, puts “fuel” back in the “tank”. With all those props on the wings, an X57 could make a controlled, near vertical descent, easily making the first taxiway.
While I’m at it, why are they reinventing the wheel? Much of aviation has this problem. The auto industry is working hard on many of these issues. But some Tesla powertrains, bolt them on, go fly. Put the powertrain $ saved into battery research. Problem, if not solved, would be a lot closer than otherwise.