At the end of the generation, there won't be a king of RPG.
PS3 will have FFXIII and FFXIII versus which will be 2 really high quality games.
Wii will have a lot of niche Japanese RPG and possibly some big titles as well (Kingdom Hearts 3 maybe).
Xbox360 will have a lot of quality games completely forgotten by the public as the games will have abyssal sales.
In the end, a big fan of JRPGs will need to buy the 3 consoles. As not a lot of Japanese will buy a 360 and most 360 gamers don't care about JRPG, the sales on 360 will remain bad.
How many cups of darkness have I drank over the years? Even I don't know...