Just to make sure - using the object model (DOM), this can be done by the application itself quite easily. However, I understand this request is for some kind of automatic refactoring.
The problem to do this on our end is the (un)ability to correctly parse the old formulas. If the datasource has changed in the meantime, formulas will no longer evaluate correctly which makes refactoring them a pure (somewhat error prone) search and replace task.
However I fully reckon some kind of refactoring might be a good addition. There’s a somewhat related request that could use the same technique here: User Variables - Allow renaming them