Controllers, refactoring, routes, filters

I was wondering if anyone had any advice/experience with when you
refactor controllers. Because the controllers are tied to the URL via
the routes, it makes refactorings a little more complicated than they
should be in some cases, especially if you don’t want the URLs to
change.

Of course the various filters with :only/except provide an additional
flex point to use before a refactoring is needed. However, I find that
excessive use of filters, especially with “long” (more than 2) special
cases included in only/except starts to smell. Perhaps that’s only
because I’m still getting used to Rails idioms though.

I’ve read through the wiki and multiple blogs without seeing any
discussion on this; if I overlooked somewhere, please let me know.
Thanks.