I was pretty much trying to point this out a while ago. The Wii was getting really bad support from Japanese developers in the beginning. Not so much from a lack of games being made (as Japanese developers were pretty much the only ones making games from it) but as in those developers never bringing the games to the west.
Over time, this turned into the problem we have today, of poor support for the Wii overall. As the market in Japan for consoles deteriorated and focused on the DS/PSP, Japanese developers focused on trying to put their major console ideas on the HD consoles, while skipping over the Wii. While in the west, most companies were already skipping over the Wii from the start or only using it to make quick cash with 'causal' titles like My Sims Agents or Blom Blox.
A lot of the reasons you can trace the 'failure' of the Wii is simply because the Japanese companies either never tried to bring their good games over to the west or never marketed the ones they did bring over. By the time Japanese companies actually started bringing over their good games, the only stuff we were getting was stuff like Muramasa, Little Kings Story and sequels to rail shooters like Resident Evil.
Six upcoming games you should look into:
