I feel the same way. I’ve watched the Democratic party move to the right starting with Clinton, and has been implementing policies that were considered conservative prior to that. I’m disappointed with Obama’s record, not because of the things he has done, but because he has failed ot move the party to the left at all.
My take on the source of this is the role of money in politics — they wealthy naturally seek to preserve the status quo, and will use their power to do so.
These changes have forced the Republicans into the corner on the far right, which was previously the domain of fringe positions that did not enter the broader conversation. Now candidates like Hillary own the middle, and the Republicans have to somehow define a platform to the right of that, leading to the cynical and hate-filled race we see this year.