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That is because I posted that before you posted your question (It was actually a reply to you calling Obama the insubstantial candidate of the two.)
Okay, changes he is offering:
First, pretty much everything has got he has got. His healthcare plan is slightly more realistic, his immigration plan is pretty much the same, but on foreign affairs he is actually the stronger of the two.
There policies are so similar that they are almost interchangeable.
Except on the biggest issue of them all. Lobbying reform.
Obama is anti-lobbying firms, Hillary is not. Now Obama's stance is questionable (He doesn't take money from lobbying firms, but he doesn't object to their staff donating) but Hillary's stance is clear as daylight - she won't reduce the power of lobbying interests in America.
And that, though it is a wild hope, though it is a promise he is likely to break, even some progress towards reducing the power of lobbies in America, would be a change for the better.