I'd defiantly want to see a 4X/RTS game involving conquering everything from Saddle-Arabia to the Crystal Empire. There would be three factions, The Solar Empire, The Lunar Republic, and the United Pony Workers Front. The plot would centre around an argument that aroused from within the royal family, causing a war between Celsestia and Luna (sound familiar?). With each of the royal princesses calling their banners, the normal ponies find they have been ruled by immortal tyrants for far to long, and take up the opportunity to strike while the royal powers are at their weakest. Obviously this would never get done by hasbro, so maybe some indie developers could take up the mantle.