>It will add an additional hour or two of effort to every resident of the state, even if they are below the state income threshold which is quite an externality.

Nope, that is false. The language of the bill only requires filing if tax is owed. There will be a handful of folks on the cusp who will need to calculate their AGI to determine their state tax liability but everyone else knows offhand if they need to file.

The language is "Individuals not owing tax under this chapter are not required to file a return..."