Neither House may have or establish any rule which prevents a majority from proceeding with a vote, or which prevents a majority from passing a bill.
Provide for majority rule for lawmaking because, just as a supermajoritarian rule is unfair in the amendment process, it is unfair in the regular legislative process.
In other words, end the filibuster.
The President shall have the power, by and with the advice and consent of a majority of the House and Senate, to make treaties.
Similarly, change the advice and consent process for treaties from two-thirds of the Senate to majority vote of the Senate and majority vote of the House. In addition to the fairness reason, laws and treaties should have similar procedures because they have similar legal force according to the supremacy clause. Also, the president and Congress have entered into treaty-like “congressional-executive agreements” (such as NAFTA) anyway when two-thirds of the Senate was not possible. This change is essentially housecleaning.