Instead of a bicameral legislature, I would have two unicameral representative bodies that serve different purposes.

The Senate would be part of the executive branch, and would be in charge of setting tax rates, budgeting, overseeing government agencies, appointing offices etc. A Senate council, elected proportionally from the Senators, by the Senators themselves would serve to take most of the power from the President. The President would no longer have the power to issue executive orders, that requires a majority vote by the Senate Council. While the agency/department heads report to the President, the President reports to the Senate Council and the Senate Council sits in on briefings. Each council member can nominate someone as a department head, however, they will be pitted against each other using approval voting. The executive branch would no longer nominate judges.

The Legislature would serve to write laws, both criminal law and trade law, as well as approving the power of regulatory bodies to write regulations. They would also serve to oversee the executive branch from a legal standpoint. A legislative council would also exist, similar to the Senate Council, with the primary responsibility of overseeing government from a legal standpoint. They would sit in on all briefings that the Senate Council and President sit in on. The Legislative Council would be in charge of nominating judges, and the Legislature would vote on them, again using approval voting.

In order for a bill passed by the Legislature to become law, it must get either four signatures from the Senate Council, or three signatures from the Senate Council and the signature of the President. In order for a bill passed by the Senate to become law, it must be signed by four members of the Legislative Council, or three members of the Legislative Council and the President.

Senators and Legislators would serve Six-Year terms, with half of them up for election every three years. Each district will be voting for either a Senator or a Legislator (or in the case that a Legislator or Senator leaves early, they might vote for both, but that will be for a half term for the early-vote). The President would be up for election every three years - this makes sure there are no "off-year" elections, encouraging maximum voter participation. Senators and Legislators could serve 3 terms for a maximum of 18 years, and the President can serve 4 terms for a maximum of 12 years. I would have districts with 5-9 seats each, 50,000 people per seat, and use CPO-STV with Schulze for Condorcet completion. For President I would use the Schulze method. With ranked voting, there would no longer be primary elections, which have even worse voter turnout. Supreme Court Justices would not have term limits, but they would be appointed for terms of 12 years and would need to be nominated again if they are to serve for longer.

The Senate and the Legislature would work completely differently. The councils have no special power in procedures, other than the specific duties they are given. For bills to come up for a vote, they need a petition with the signatures from 30% of representatives. To prevent abuse, a petition with a majority can prevent a vote. There would be no committees requiring approval, although working groups can be formed which can then hold hearings to determine the best course of action. The working groups have no special power, they are just a way to organize. Basically, no one person is given significant power to the point where they can prevent a bill from passing by themselves. A vote of 60% can allow a bill to come into law with less than four signatures from the council, but they still need at least one.

If the government fails to act on an issue the public wants, the public could bring a referrendum, allowing them to bypass the normal processes and vote directly on an issue during the next election.

Besides minimizing the power given to any one person, one of the big advantages as I see it is that by having two representative bodies, you can vote for different parties on matters of law vs matters of government policy, allowing you to be a bit more granular in your voting. The longer terms is to make sure there are enough experienced politicians in office, while the term limit is to make sure that there are at least some people not worried about re-election.

CPO-STV makes it easier to get elected, because you don't need a plurality in your district - anyone with more than (Number of Ballots Cast)/(Number of Seats + 1) ballots (16.7% for 5 seats, 10% for 9 seats) where they are ranked first is guaranteed a seat, and then it is still possible to win if you don't get that many. This makes it less costly to win, minimizing the effects of campaign contributions. The fact that the system minimizes the power held by any individual minimizes the effectiveness of lobbyists, and reduces the problem of pork barrel spending and corporate-sponsored changes to bills.