"Nintendo Hearts" (crossover with Square-Enix) RPG would outsell all four of those combined. 3-4 million from Japan alone and probably another 4-6 million worldwide minimum IMO. Mario x Pokemon x Final Fantasy x Dragon Quest x Zelda. Game over. Could be an on-going franchise that makes Nintendo + Square-Enix a ton of money.
Yes, even more than Pokemon MMORPG ... MMORPGs have smaller fanbases, and for what's a kid-centric franchise it would work as great as people think. A monthly subscription fee would be a swift "no" from a lot of parents.
Metroid fans need to kinda stop with the complaining. Yes, we get you want a new Metroid (I'm a F-Zero fan, would be nice to have a new F-Zero, seeing as how Metroid has gotten like 3-4 new instalments since the last F-Zero), but Metroid is never going to be a big seller. It's too slow paced/solitary of an experience to gain a big mass following.
It sounds like from what Miyamoto and Tanabe have said one is already in development for Wii U anyway (perhaps centering around the Hunters concept?).
