I said it going in, and I'll say it coming out: Wisconsin was actually reasonably favorable terrain for Obama, whatever you may have heard to the contrary. As I laid out here, it's a lot like Iowa demographically, except younger and more African-American. (The 2008 exit polls are actually somewhat confusing on this question, since they reflect who turned out for Obama--e.g., an unusually large number of young people in Iowa--rather than relatively fixed demographic features of these states.)
In general, I'm not sure it's quite right to extrapolate from Wisconsin to Ohio. While it's true that both are, broadly speaking, Midwestern states with a lot of working-class whites, my hunch is that blue-collar voters in the upper Midwest (states like Iowa, Wisconsin, and Minnesota) are more progressive on race than blue-collar voters in the Rust Belt (Ohio, parts of Michigan, western Pennsylvania, western New York.)
So, for example, via Mark Blumenthal, I see that ABC's Gary Langer says Obama pulled even today among whites without a college degree. That's a big development for him--as this Washington Post chart shows, the best he's done so far in a (more or less) two-way matchup is 50-37 in California and 57-42 in Virginia, at least if you ignore Illinois. On the other hand, there's one other place where Obama was basically even among working class whites: Iowa. (Though Edwards was obviously still in the race then.)
Anyway, my point isn't that Obama's not expanding his coalition. I think he is. It's just that an expanding coalition in Wisconsin or Virginia isn't the same as an expanding coalition in Ohio.
Now, Texas, on the other hand...