It's interesting that the air is going into the engine from the top of the cylinders and the exhaust is on the bottom. This would allow one cam shaft to operate both exhaust valves and the other to operate both intake valves, unlike the present twin-cam engine, where the gas flow is back to front.
That change would allow variable valve timing with separate control of the intake and exhaust valves, like BMW uses on their car engines. Why else would they make a change like that? It will eliminate the exhaust pipes coming out the front of the engine, which are one of the thins that give the boxers their distinctive appearance, and would also seem to require a sharp bend of the exhaust pipe just as it exits the cylinder, to keep it away from the ground. Variable valve timing might justify this change, but I don't know what else would.
There will need to be a water pump somewhere. Early 3 cylinder SAAB cars had the water pump on the back of the alternator housing (actually it was a generator back then), so a single pulley and belt could drive them both, on a common shaft. This would seem like a good arrangement for a GS, since it would place the water pump up where it can't be damaged.
One thing I like about the air-cooled GS is that the riding experience is devoid of blasts of hot air off a radiator, which many water cooled bikes suffer from. I hope they manage to maintain this advantage. If not, that alone might make me keep my present bike.