We should amend it [0] so that any state may subdivide within its own borders without the consent of the Senate, provided that no subdivision is smaller (less-populous) than the smallest current state.
In other words, small states don't have to give up their disproportionate representation in the Senate... but they cannot use that power to monopolize being small either. Any state above a certain size (>2x the smallest) may decide that its constituents are best-served by fission.
This adheres to Article V, Section 5, since no state is being deprived of "equal suffrage": Each state has 2 senators, just like always.