I'm glad Vim is running fine on Rosetta, still, if you wanted to compile it from source, it really shouldn't be too hard.
(Rust is a harder problem, so I wouldn't worry too much, still, once the dependencies are downloaded and compiled it's usually fine)
$ file `which vim`
/usr/bin/vim: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64e]
/usr/bin/vim (for architecture x86_64): Mach-O 64-bit executable x86_64
/usr/bin/vim (for architecture arm64e): Mach-O 64-bit executable arm64eIt hasn't been merged yet as some of the dependencies aren't available, one of them apparently being LuaJIT, but if you build it yourself without that it shouldn't be a problem.
Also need to track down and install all of the dependencies, and the dependencies dependencies and all the way down, and figure out the right configure flags to pass, and what environment variables it needs and where it expects to look for header files and the like.
Doing all of that from scratch takes hours and hours. Homebrew lets me not worry about that, and instead be productive.
The nice thing is I can just wait out the compatibility issues re: arm migration, especially with some of the third party crates my rust projects depend on currently failing to build.
Also, the ARM version of Homebrew is not yet ready for primetime, there is a ton of software that doesn't compile for ARM yet (Including MacVim).