Well, on one side, it's a stupid move abandoning the best selling console of the generation.
On the other side, it's logical for 3rd parties to push consoles with weaker (as in less dominant) first party, so they can have larger piece of cake on their market. Plus, the market is less risky, the recipe for success has been set long ago, and all you have to do is to follow it and invest sufficent amounts of cash and talent. Opposed to researching what the weird wii demographic actually want from them.
Will Nintendo suffer because of that? Absolutely not. However you spin this, the Wii market will have atleast 80-100 million potential buyers, and mostly Nintendo releases to buy.
What I think Nintendo should do is, establish another publishing brand (N obviously doesn't want to be associated with lots of mature content) and buy a couple of talented studios (they're cheap now), and start some hardcore/mature projects. Establish some kind of guidance from key Nintendo people on their projects, and release the games under the newly established publisher. But Nintendo should do it asap.
The added benefit would be great potential for entering into the next generation successfuly, retaining the casuals which will have some brand loyality, and gaining core from the PS3/X360 markets with the announcements of mature games.
Then they would even have the strenght and ability to introduce more rigorous quality control of 3rd party games on their next-gen offering.
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