Renaming functions is not that hard without an IDE. Or if you're good at using the shell with grep/xargs/sed you're good to go.
The thing is that IDEs can save you a few minutes in these cases if the function to be renamed is used across many files. However the IDE also sucks up a lot of your life in exchange; you're forced to use the IDE's idea of how projects should be laid out, they need to know every file you use (otherwise they can't search/replace), they're not happy when you use external build tools, many of them get confused if you use external editors (no IDE code editor is even remotely close to the usefulness of emacs), and sadly in this day and age, so many of them are just plain awful (none of the whizbang must-have refactoring features that people rave about, just a lousy editor with a lousy debugger). If the refactoring is so awesome then someone should come up with a tool to do that without the agony of using an IDE.
Another hint that many kids who follow behind Microsoft don't know. If you don't use Microsoft's stupid variant of Hungarian notation then you don't need to rename your variables if you change their type, so either don't use Hungarian notation or else use it the way it was intended to be used (prefix by the use of the variable and not the type).
Right now I'm forced to use an IDE based off of Eclipse for one project, because it is the only debugger for a particular chip unless we switch over to Windows. It's absolutely brutal to use. Sloooow, crashing a lot, a bit confused about ELF format, unintuitive, hours of wasted time trying to figure out what should be simple, and so forth. So it's the worst of Eclipse with the worst of unnamed vendor (starts with tee and ends in eye), and the vendor isn't even using it internally.