Holy crap! I hope you are never president. (I guess you would be a dictator with that power)
If I could mold the government, I'd rectify the excesses of our federal government and reign it back in. Specifically, I'd do the following:
Repeal the 17th ammendment - US Senators are meant to represent the state governments and should be elected by and report to the state legislatures. These massive state-wide elections wasting millions of dollars need to stop. And senators need to do their job and represent their state government interests... not investigate baseball, school lunches, entertain celebrities, etc. Ridiculous.
Slash the size of the Federal Government - Because a need exist doesn't mean it is the federal government's job to fulfill it. Retirement, health care, unemployment subsidies, education, etc, etc should be handled at the state and local level. The federal government should be limited to national defense and inter-state commerce. I would eliminate the majority of the federal government as well as put a cap on how long Congress is in session. When state legislatures are in session, the US Senators should be THERE, not in DC. When they are in DC, they should stay in a barracks and NOT set up residence. Same with US Representatives. Spend the time in your home districts when not in DC (and stay in those same barracks when Congress is in session).
Get rid of the Federal Income Tax - Get rid of this tax and dismantle the huge infrastructure (IRS) that is needed to manage it. Go with either a MODEST national sales tax (my preference) or have each of the states pay a certain, representative sum to the federal government for it's operations. The states can fund their budgets however they like...state income tax, sales taxes, etc. If we don't like how one state does it, we have the choice to move to another state.
Term Limits - Two terms max for all offices. And no retirement plans, special health care plans, etc for members of Congress. Serve your country and then return to the workforce. The president is a special case and should be treated as such (inline with current policy...although I don't see why we need to fund their libraries or allow them to rent out space to secret service agents. They should provide lodging for the secret service...buy a house with a spare bedroom for crying out loud!)
It time to stop believing that it is the "rich people's" fault when we have massive federal debt and deficits. This blame lies squarely on the shoulders of the Federal Government and our willingness to allow them to continue to spend like idiots. The federal govt doesn't need to have its hands in all the various cookie jars (and shoiuldn't). The Federal govt should not play the role of our safety net. If we want/need that, set them up locally at the state/county/city level. The Federal govt should have a very specific and limited role (as the forefathers intended).