I think it's safe to assume Super Mario Galaxy will hit in Q2, probably April or May. Metroid: Other M is a bit of a mystery but we know that Nintendo would not have wanted to show it if it was over a year away so I think Q3 for Metroid: Other M at the latest but it could come earlier than many expect.
The two that may hit for holiday 2010 are Wii Vitality and Pikmin 3. I can't see Zelda being ready in time and I think Retro Studios next game will hit in Q4 also and so Nintendo will want to spread the releases a bit..
Basically what you are saying will not happen.. I can definately see Nintendo shifting their dev resources upstream a little bit with third parties satisfying the expanded audience quite well, Nintendo will slowly try to bring in more of the core audience.
