The effect on state taxes is something I have not seen discussed anywhere until this thread. There is bound to be some really negative consequences for states that base their tax on the federal Taxable Income line, which is AFTER deductions and (formerly) exemptions. Hence, if taxable income goes down because of the doubling of SD (for example, for retired couples with no kids), they're going to collect less tax.
Here in California, taxes start with federal Adjusted Gross Income, tweaked for things that are or aren't taxable in CA (mostly SS isn't taxed, and state taxes aren't deductible). Then the generous Standard Deduction ($8472 for couples) is applied. We have an "exemption" of $114 per person, double that for seniors, but it's actually a credit on the calculated tax. So there shouldn't be any significant effect on our tax collections.