In short, I appreciate the championing for the middle class. I really do. Here's why it doesn't work --
1) A speech that's all sob-stories about individual, lame-ass people makes for a lame-ass speaker.
2) Any dem is going to fight for the middle class, the individual, the little guy. It's part of the party agenda. If you make it your main running point against two people declaring eras of "change" it gives the impression that you have nothing original to say.
3) We have a federal government, we have state and local governments, and we have constituents. There is a food chain. Perhaps as the president it would be best to focus on improving state and local governments so they can take care of individuals. If you worry primarily about the individual on the presidential scale, you are applying for the wrong job.
Good guy, good ideas, just the wrong focus for a national leader.