Homeowner's Property Tax Lottery

It seems that once again, Mayor Bloomberg is going to give New York City property owners a rebate of $400 in the upcoming budget along with over $20 million for affordable housing. These property tax rebates are starting to beg the question: Why don't the just lower the property taxes here in the city? Of course, politically, that's not a bright move since it's harder to raise them again. It would, however, be a great thing for homeowners to see their property taxes lowered while their schools get better. Too idealistic for this world?