I'm not aware of any languages so simple that renaming an identifier and its usages isn't a useful feature.
sed -i 's/foo/bar/g' **.rb
A bit of forethought when first naming things works wonders, too.
You need an editor that can understand "this usage of 'containers' refers only to class 'Zoo', so I should find all variables of type 'Zoo' which reference the 'containers' field and change those."
hence
> It's not precise, so it might take some manual work and tweaking with the patterns
and like I said,
> for how often I've had to rename identifiers, it works good enough to handle the bulk work.
so
> You need an editor that can understand
No I don't, because renaming across many files is rare enough that I don't need it.
Most of the time, I do refactoring before it's gotten out of hand and so regular vim features like I mentioned in another comment are typically enough.
In other words, I think such understanding by the editor is too much complexity (and language-constrained, at that) for little reward.