The other genres are so much more European and much easier to make than a japanese RPG, which can take years to finish. There is not such a huge call for them, as there are plenty on actual japanese machines.
But if we can make AN JRPG Maker for Amiga 68k for exaple, we can save years as in 6 to 10 years to years 2 to 5 years for example. Since there are over 4 billion people in the world, let us 1000 out of the huge human population use the rpg maker and make rpg games for amiga...problem solved.