I would like any evidence that the first paragraph is correct. State governments are not magically immune to the influence of lobbyists. See the governors of VA, NJ, (ex-)IL for examples of this.
They are not less immune but the damage they can do with their corruption is not counted in billions and the scope and return on investment much lower - i've read about ROI in the ballpark of 20,000% at the federal level. The more power in one hand, the more profitable is to buy said hand. Having everybody important conveniently in one place and being out of sight of average citizen sure helps.
As for local values, I would argue that allowing that to define laws is insanity. Are people citizens of the same country? If so, then they all should be dealt with identically, regardless of who they are, what they believe, or even more so, who their neighbors are and what they believe.
Why don't you believe in self determination and what's your take on the affirmative action then?
The only way you can achieve something like that, with the absolute equality, is to you extract the lowest common denominator from all world views. There would be a problem though, because it would be something like the US constitution and the bill of rights, but without the reinterpretation nonsense.
Universal agreement to more than that is impossible because different people weigh freedom, safety, convenience and what not differently and there is no way around it.
Btw, shouldn't you strive for equal rights for all people? The superstate is as arbitrary as the state. Why does the federal govt have the right to segregate people to 'Muricans and these other dudes usually with dark skin who can be droned just because?
And social issues aside, how are you going to apply your identical solutions to economic problems to places with varying levels of economic activity? Uniform minimum wage doesn't work for all states, it's either too low for SF, LA, NY or too high for the rural South or American Samoa.
On competition, what do you propose to do with states that find a bad solution?
On the lack of competition, what do you propose to do with the federal govt finding a bad solution? Oh right, nothing. And you most likely you wouldn't even know how to fix it, because you wouldn't have 30 convenient examples telling you how to do it right.
Are you sure the ACA is going to pan out? I wouldn't be. And how do you feel about the NSA spying on the citizens? What are you going to do about it?
There's no reason to "pray and hope" for a good outcome from some disconnected ruling class. You fund government agencies with tasks.
So who decides what their task is, not to mention what the definition of 'is' is? Lawmakers do. Let's see...
the Patriot Act?
the NSA spying on citizens?
the TSA molesting children at airports?
No Child Left Behind?
the SEC doing nothing to curb banksters?
Monstanto owning their regulators?
the FDA generating exorbitant costs to the pharma industry to the tune of billion dollars per trial?
Yup, sounds like the federal govt is a neverending stream of successes. You might want to rethink if it's as simple as creating an agency with tasks.