I don't understand why you need an IDE, I believe Rust is simple enough that you can work on things in Notepad++ or Vim or Emacs.
- Autocompletion
- Mass rename
- Source formatting
- Integrated debugger interface with breakpoint insertion and overlying of state on source
- Integrated VCS control
- Automated deploy
- Error display
- Automatic importing of modules
- Source cleanup (Automatic loop transformation)
- Automatically building my project
I understand that there are other tools that do the tasks better, maybe even faster, but that's not what I want. I want to be able to learn one thing, and learn how to use all of it's features well.
Not only do you have a package manager, but a build system.
Source formatting: rust.vim + rustfmt
Automatic building: https://github.com/passcod/cargo-watch
Error display: tmux, terminator or iTerm2 split planes
Rust has pretty good tool support in vim and Atom, for example (can't speak for the rest). We don't have stellar IDE support yet, but it's on the to-do list: https://www.rust-lang.org/ides.html
Personally, I don't miss IDEs. I like the approach of small, single-purpose, composable command-line utilities more.
Split panes are a poor substitute for actual error display integration; highlighting the errors in the source-code viewer, combined with a cross-linked list of errors is far more useful.
However, the reason why so many people in this thread persist in suggesting that these tools are worth learning is that turns out most of these tools plug-and-play with whatever new language you feel like learning 6 months or 2 years or more from now.
Vim is one of the more popular editors to use in conjunction with this plug-and-play philosophy; if you have a change of heart and want to take a dive into learning to use Vim as such, I'd recommend Vim as an IDE[1], which addresses a lot of the points you brought up in your list of things you wish an IDE had.
You probably noticed how useless racer is on the command line: type code in your text editor and then when you want a completion, you go to your CLI and type "racer myfile.rs row,column" and there are your completions! :) Jokes aside: it's clearly superior (and intended) as an integrated tool than as a command line tool.
I'd argue that a debugger can offer the same kind of power being an integrated debugger as the (admittedly silly) racer example.
People love C# for that very reason, once they get used to Visual Studio, convincing them to switch to something with very limited IDE support is a tough argument. Most people have better things to do with their life. Rust will get there though, just give them time.