I don't think B and C tier projects bombing on Wii really is the problem for 3rd parties in Japan, because I doubt they expected them to sell well. As is plainly obvious now, the biggest problem they face is the massive failure of PS3 to sell anything like respectable numbers over the key buying season, or sell decently for the year, and none of its sw sold well. With such increased dev costs, this is something they must be shitting themselves about, because PS3 sw really isn't selling well anywhere.
When you bank on a system like PS3 being your main money earner, and reality unfolds the way it has, you're going to be in massive trouble. 3rd parties' problems are entirely from banking on the wrong horse. The titles which can realistically be considered close to major on Wii, i.e. DQS, REUC and RE4Wii, have performed well. Had these bombed, then yes, there would be a clear inability for 3rd parties to sell sw on Wii, but they didn't so there is no specific Nintendo bias conspiracy amongst the mass market. It's up to 3rd parties to find out what consumers want from them in this new market in Japan, not Nintendo's responsibility at all, because there is no concrete definition of what constitutes a hit. Nintendo has been experimenting and found a winning formula, for them, but what that is cannot be packaged in a way to be handed to 3rd parties to say, 'here, do this'.
3rd parties have to find their own way on Wii, as they have on DS, and Nintendo is obviously working on getting as many top level games from them as possible, but it's going to take time. MH3 will only be the beginning, even Wada from Square-Enix has now realised what Wii has become. Over this next year announcements will be coming, but again, it's not Nintendo's responsibility to have those games sell, because they're busy enough as it is, it's entirely upon the shoulders of the 3rd parties. The market has changed at the hands of consumers wanting the change, not a specific developer.
Home console gaming can be huge in Japan, but it's up to each 3rd party to find out what they can use from their own strengths to create big sw sales, not by attempting to copy verbatim what Nintendo is doing, because if they do this they will probably fail.