I heard the same rumor, but also heard that the details of such a "law" could be very hard to work out.
For us, the appreciation has been great, but for younger people trying to afford a house, as I said, their taxes per month, if they bought my home today would be more than any mortgage payment we ever made.
The "save our homes" cap is what kept us in our home, when we needed a bigger house because my MIL needed to move in with us. We renovated, adding extra rooms, deck, etc. (and I'm glad we did, our taxes did rise, but assessment was only on portion that was added), but it would have been easier (maybe cheaper, in the short run) to just find another home in the area, especially with the building codes in place, since we had to bring our entire house up to Miami-Dade code (but the extra expenditure in taxes if we had relocated would have been huge.)
That's too bad but not surprising. This rapid appreciation will only serve to keep homeowners where they are, limiting inventory and pushing prices up even more. With the first wave of baby boomer's reaching retirement, demand will only increase as they look for warm weather, golf courses and a place to put their boat. This bodes well for places like St. Pete, Sarasota and Naples.
The only thing that could derail this, IMO, is the incredible cost of wind insurance. If we get a few more big hits over the next few years, we might see more insurers leave the state and force an increase in premiums to the point that insurance costs residents more than their property taxes.