For a stage eligible camera owners to buy an Epic-M, it means they will either end up buying two Epic cameras (1 M, 1 X), or sell their place in line for the Epic-X.
Furthermore, Stage 2 and 3 owners currently expect some camera accessories (LCD, modules, module adapter, Redvolts and charger, etc.) as a loyalty bonus. If stage eligible camera owners were able to utilize their trade in value toward an Epic-M, it might very well sway some to go that direction. However, it would still cause confusion among Stage 2 and 3 owners until there is more "bonus module" information out there.
My guess is that Red wants to wait and see where the Japanese price environment will level out. Then they will crunch the numbers and refine the new stage system.