>Also, capital gains is a flat (regressive) tax, and social security taxes (also flat) top out at an income of $132,900. If those were placed under progressive income tax brackets with no cap, I think many of these problems would go away.

This I think is an excellent point. So many wealthy people make far, far more than the SS cap; forcing them to pay more into the system would certainly shore it up a lot. And capital gains should be taxed no less than regular income, if not more since it's passive.