Should former Roman land be given to the Italians? Should the Louisiana purchase be undone because it was the result of a military defeat in the Napoleonic Wars? Should the non-first-nations parts of California be returned to the Mexicans because it was ceded in the Mexican-American War under the Treaty of Guadalupe Hidalgo? What framework do you propose we use to decide which land is worthy of sovereign rule - and which isn't? Which groups are worthy of sovereignty, and which aren't, and on what basis?
I think all groups should be represented within the government and there's no reason to revisit the question of sovereignty because there's no framework that makes sense. There's no easy place to stop that isn't totally arbitrary.