I recommend that voters read the actual language of the proposed constitutional amendment before passing judgment on it. Everybody seems to assume that it only permits graduated rates similar to federal taxes (higher incomes taxed at higher rates).
In fact, nothing in the amendment language precludes inverse graduated rates (higher rates on lower incomes).
The legislature would never do that, you say? Tax breaks for billionaires are politically impossible? Dream on, all you taxpayers about to the plucked.