I think what people are wanting is a change from the Clintons.
The Clintons have been around too long and they have been the face of the party too long. any tool to get rid of the clinton baggage (Gore and Edwards included) is a positive change for the Democrats and America.
I think Obama is tapping into the Perot angst about how many feel that the parties scream and shout and put on a big show of how different they are at election time, and then make deals behind the door and are so very friendly to each other in private. People are feeling scammed and hurt, and too many of those deals are a manner of ripping off the people. Like the wars they have over the percentage of tax on everybody, but then there are neat little loopholes that let the connected escape taxes on anything. If you are connected.
Of course, Obama strikes me as an empty suit who is very willing to negotiate anything for anyone, as long as he gets his commission. His talk of change is his desire for any of the loose change you have left in your pockets after the Clinton crowd gets done with you.