I prefer keeping many things at the state level. It’s much more difficult to be involved in government when you’re trying to vote in a pool of 350,000,000 people with different interests. Democracies lose effectiveness as population increases.
There is a good argument (for the good of the country as a whole) that sales tax should be harmonised.
Over time I've become more interested in the loose confederation of states and decentralization of power over consolidation of power at the hands of the federal government. I think the US has too large of a population with an increasing amount of differences to really effectively govern. If parents want to teach kids that the earth was created 6,000 years ago in their state, who am I to say otherwise? Vote with your feet and $$. If I don't like how California handles businesses like Uber and Lyft, same thing. At least at the state level though you right now have some reasonable measure of involvement. I can email my state representative and actually get a response. My federal one? Not a chance.
In order for states to take back power they need the income.