Currently, not only does the existing homeowner have to pay less taxes (if prices increase over 2% YoY), but later when they sell their house they can cash in the entire difference. That doesn't seem fair if the entire point of Prop 13 was to protect retirees from being kicked out of their house. So instead, make it so that when the house is sold they have to pay in backtaxes all the difference between the FMV based tax and what they actually payed from any profit they are making on the house. Also stop all means of being able to pass the house between generations without re-assessment (that is currently possible in many states in CA).