Is the midwest crucial for victory?

[opebo]

The midwest is close but not changing much.  Nevada, Colorado, Arizona, and New Mexico are the fastest changing region.  One might possibly throw in Virginia.
 
That doesn't mean your point about OH-WS-IA-MN-PA isn't valid, I'm just saying the Southwest will become about as close as that area as it becomes more Democratic.

[opebo]

Of course MN,WS,IA,OH,PA add up to 68 electoral votes, while CO,AZ,NM,NV are only 29.  Even throwing in VA as another possible soon-to-be-swing-state-due-to-demographic-change only raises that total to 42.  The midwest does seem like where elections will be decided for quite a while, assuming Florida stays GOP.
For example:

Though I really doubt PA is trending GOP.

[opebo]

Here's one using the shading to reflect leans in 2008:
Solid to Leaning Democrat - 242
Solid to Leaning Republican - 249
Tossups with no lean  -         47