For instance, do you think things would have been much different under Hillary than under Obama? I don't think so. They're both establishment figures who's real masters are the big corporations -- that's where they get most of the money for their campaigns.
They might have been different.
For one, expectations. Obama campaigned with a really progressive message, which, coupled with his race, I think fooled a lot of people into thinking he was somehow really different, when in fact he really wasn't. I think a female president might have ignited some of the same wishful thinking, but perhaps not as much as the racial differences. Plus she's something of a known quantity from her time as First Lady and Senator.
I also think Obama, with very little Senate experience, came into the office relatively weak in terms of political leverage. Hillary Clinton would have come into office with a ton of political leverage, after decades of political involvement with her husband, her senate experience and a ton of points where it really counts, fundraising for the Democratic party. The Clintons have a machine of their own.
Hillary may have had a lot more IOUs to call in and could have been able to set a course of her own more easily; Obama clearly has been weak in this regard and often has trouble engaging Democratic legislators.