We could definitely do better with removing variables. It’s not as simple as it sound though, say for example during your refactoring you remove the variable but then decide it should have just been renamed, too bad, if we remove any references to it you would need to manually go in and re-add it. It’s doable, just needs some thought.
We already handle renaming of variables, if you rename a variable we attempt to find all references to it and rename those.
We will look into this, but I can already tell you ( because I did most of the work on supporting variable reference renames) that it’s not a small task.