The current presidential primary system has the first four, and arguably most important, primaries in the following states_ Iowa, New Hampshire, South Carolina and Nevada.
My biggest problem with this arrangement is that none of those states have a major urban area. Las Vegas is pretty far down the list in terms of city size, and is odd enough demographically, that I don't feel like it does a good job of representing urban interests.
As much as people like to play up the red state/blue state split, or the Northern-Southern angle, I think the real divide in this country is between the urban and rural populations. Because of the nearly even split, Missouri really exemplifies this dynamic. Urban and rural areas split very neatly on issues like educational rates, transportation issues, energy policy, and so on.
Look at this map of the 2004 US elections broken down county by county. To a large extent, what you see are mountains of blue surrounded by lowlands of red. That's the urban-rural split in action. In essence, what the Democrats are doing here is leaving their base out of the primary process, which seems foolish to me.