Well, if the subs can do just a good of a job as the regular teachers..... fire them and hire the subs.
No brainer.
..and legislate the requirement that salaries, benefits and retirement can be no higher than the average equivalent private employee amounts. No exceptions.
A new State Constitutional Amendment would not hurt : No Future State expense can be incurred that is not funded in current budgets, and the moneys for a specific purpose may not be spent or borrowed to meet the expenses of the General Fund or emergencies of any kind.
A responsible legislature with an IQ of over 60 should at all times maintain a state reserve for emergencies that is adequate to meet the average cost of actual physical emergencies of the previous ten years. Again, those moneys shall not be used for any other purpose under penalty of criminal incompetence. That would include labeling a Gay Parade an emergency for purposes of funding it.