Yeah, I think it might be a programming-language cultural thing. Most refactoring tools are written for Java and C#, so the people with experience writing refactoring tools have worked out how to solve the problems when they have certain assurances. But it really should be possible to write usable refactoring tools for ruby and python and javascript - you'll have to do a little more work to figure out name collisions between variables and methods and there's going to be ambiguous metaprogramming stuff like using strings to lookup instance variables, but having good tooling in the cases where you weren't using metaprogramming might encourage programmers to use a more concrete coding style, and that's probably a good thing. (Java has the same problems when you use a lot of reflection. So people don't use much reflection!)
YES! And I bet that a little bit of heuristics, a little bit of machine learning, and/or a little bit of user feedback (say, a button that tells the tool it went to the wrong function definition) would help such a tool cover a few more of the difficult cases.
This ought to be a classic case of "worse is better", which is why I'm surprised to see that people seem to shy away from it.
