I reject the idea that "political feasibility" can ever be a conversation-ender, especially when put against a true injustice.
Prop 13 (and all other subsidies for special interests) are unjust and unsustainable; they persist due to the support of these special interests (and the indifference of everyone else). With the proper education and elegance, one can hope for a day that we can see through this and implement the right policies.
And incidentally it's probably easier to argue for fairness and fiscal responsibility than to argue for bulldozing open space to put in a high-rise apartment.
At any rate, I'll always fight for dialogue upon the BEST policies before settling upon a compromise, as this will guide us in the right direction.
When this refers to the beneficiaries of land grabs (either directly or indirectly), I don't think an appeal to the natural rights of property owners holds much power.