We beat this one to death before. Yes, ideally it would be horizontal and designed into the primary to run in an oil bath like on a 4-stroke. That does not justify a complete redesign for only part of the market, IMO. For those that want/need it its a good tool that seems easily servicable and removable if neccessary. If you keep the wear surfaces clean and greased with a good lube (I suspect a moly paste would work good) and use it as neccessary (for restart) things should be OK. What I would have explored(and perhaps they did) was integrating a small Li Ion battery into the starting system's case, down low on the motor. This would make it more modular, lighter, and still have adequate capacity for restart functionality.
Do 300s really need a big PV cover for more low end?