I'm a java refugee and used to make heavy use of the refactoring tools in eclipse. It's definitely something I miss from my old workflow.
Given you're using BDD there isn't really anything to be concerned about when using regexes etc. to manipulate the code. I'd say that learning to use the command line better is essential if you move to a dynamic language.
With regards to the test suites being larger due to type checking I think it's been fairly well established now that this isn't the case. Those types of errors are always shown up when testing other aspects of your code, I can't think of a single case where I've written tests that do any type checking.
In the end I find that losing the refactoring assistance is a tradeoff that I'm happy to make in exchange for the increased expressivity and productivity I enjoy with rails.
Find and replace is probably the only time I use the command line to actually modify the code. I could use a text editor to do this but favour the power I get with the command line(using ack and sed). Using the command line isn't necessary to work with rails but it is favoured within the culture. Generally people use it for everything from running the server to checking code in and as mentioned, refactoring.
