One of the zombie notions out there which the press plays along with is that "complexity" in our tax system is largely due to the existence of tax brackets.
Nobody will spend one second less thinking about their taxes if there are fewer tax brackets. Getting rid of tax brackets does not make the system "dramatically simpler."
It's a nonsense justification. Even if you're a Luddite using tax tables instead of online preparation, there is still absolutely zero extra math involved for the taxpayer. If it were up to me we'd have a much more stratified system with the top income brackets subdivided into many more, with increasing marginal rates. And it wouldn't be any more complex. What that would do, and what proponents of the "simplification" actually hate, is distribute tax burdens more fairly up the income scale.