Without literally personaly rewriting the thing, some obvious points:
Add the following requirements for all elected officials:
- must disclose all personal financial information and pass an IRS audit
- must have ZERO outside income and/or assets during the term of service
- must pass a full criminal background and security clearance check
Abolish the Electoral College.
Institute proportional voting for House Delegations, meaning that when voting for House members, a voter would cast a ballot for the party rather than the individual candidate. The House delegation for that state would then be apportioned among the parties based on that vote. (If Party X got Y% of the vote, it would get Y% of the House seats for that state.)
Congress would have the EXPLICIT authority to subpoena any witness or document it felt necessary to perform its Oversight function of the other branches of government. Compliance with said subpoenas would be MANDATORY on the part of those summonsed WITHOUT EXCEPTION. Classified information would be protected under the usual standards, meaning Congress would not be able to publicly disclose the information, but could not be denied it for its own purposes.
Establish a formal Fourth Branch of the Government to consist of the administrative and law enforcement agencies and their personnel. The personel of this branch would be drawn ONLY from the pool of applicants who had demonstrated their qualifications based on objective tests such as the Civil Service exam. NO elected official would have ANY say in the appointment of regulators, judges, etc.
Adjunct to the above: all laws must apply equally to both the citizenry AND government. All elected officials would be fully investigable, indictable, AND ARRESTABLE even while in office. Again, no elected member of the government would have any ability to influence or interfere with those actions.
Amend the First Amendment to explicity state that free speech rights apply ONLY to acutal flesh and blood persons. Corporations are NOT persons for the purposes of the 1A. Explicitly state that donating money is NOT a form of speech and may be restricted to ensure a few large donors cannot effectively "buy" elected officials. (I'm honestly on the fence about outright publicly-financed elections.)
Further Amend the 1A to explicitly EXCLUDE all forms of advertising, deceptive news articles (those that cannot be shown to be based on actual objective facts and information). ALL sources must be documentable and aviailable to fact checking.
Amend the 2A to state that any person wishing to possess a firearm MUST first provide evidence of a clean criminal record, and of passing a mental health exam. If any person later loses the ability to pass either requirement, their arms must be immediately confiscated.
Pass a new amendment making it mandatory to vote, and establishing a 2-day period for any called election which would be mandatory paid time off for workers.
Most importantly, once and for all formally state that we are ONE United States for the purposes of law and governance. ALL citizens must be treated the same by the laws and programs EVERYwhere within the US. This would include participation in all Federal benefits programs such as Medicaid, the ACA, etc. NO more "states' rights" nonsense.
Not every change I'd formally make, but most of my major points.