You'll get a hundred thousand sales for the upgraders alone, a couple hundred thousand more that will just want the game because it's Dragon Quest. Then a few hundred thousand more who were holding off for the definitive version of the game on Wii U. So I think sales will be fairly high.
The main reason sales are lower than other Dragon Quest games is because most fans of traditional style RPGs don't like Online games. The reason why Warcraft was successful was because the Warcraft/Starcraft fanbase like online games.
People who don't think a Dragon quest game will do well in Japan obviously are unaware of the popularity of the franchise in that country.
The real question is how much value will this attention will bring to the Wii U in a time when Nintendo has no other big games on the schedule to build on that attention.
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