As Tim said the homestead exemption is a local/state issue and varies in value from state to state. As far as 1031s go, I doubt you'll see any change there as it's way too valuable for larger businesses than for RE investors.
The first time I ever heard of a 1031 was back in the '60s (I didn't buy my first house until '71) and it involved the owners of the (IIRC) then Baltimore Colts and Los Angeles Rams trading NFL teams. I don't think you'll see the day soon where we start taxing unrealized gain.
As far as where we could raise some tax revenue, I put out the following without comment as to their political ramifications;
1. States/municipalities begin to crack down in "sales" (although they use a different name for it) tax collections on sales over the internet. Big gaping hole there.
2. Raise the top rates, even back to what they were under Reagan or Clinton.
3. A SIGNIFICANT tax on gasoline. Other than the big producing nations of the middle east we probably have the world's lowest tax on gasoline, forcing us to spend TRILLIONS per year maintaining the world's only (in the true sense of it) "Blue Water Navy, the most powerful air force and one of the most expensive armies.
In order to lessen the tax hit on lower wage workers it should be phased in and accompanied by a decrease in the personal income tax on lower wage earners. I'd personally like to see a ONE DOLLAR per gallon (to start) phased in twenty five cents per calendar quarter. As long as housewives are driving one kid 1/4 mile to school in a Suburban or Expedition, or one commuter is doing 15 MPH in bumer-to-bumper rush hour traffic in the same, GAS IS TOO CHEAP.
Frank