momentum, once lost, is really difficult to get back. i honestly don't think there is anything nintendo can do for the wii that will do anything but slow the decline.
with project cafe announced third parties won't green light any new games most likely.
nintendo themselves are going to have to dedicate resources to project cafe so that it has a good launch not to mention try and gain some momentum for the 3ds.
you can't just come out and release games at the drop of the hat. it takes at least a year, generally longer, to create one so short term game releases isn't really isn't an option.
if the price cut doesn't help, i don't think nintendo has any option left other than to try and kick-start the next gen as soon as possible. at least with cafe they are likely to get a lot of third party support in the form of ps360 ports. i'm not sure that is going to be a successful strategy because of the 100Mish existing ps360 owners but it has got to be at least a better situation then where they are now.
nintendo's greatest failure ... when they were making 1 billion dollar profits they should have invested that back into the platform. farm some games out to 2nd party to guarantee a wide range of good software.