[vitd]

> Lack of refactoring support for Swift is currently baking my noodle,

Yeah, I hear the refactoring tools are great, but they don't work with C++ either, which is what most of my source-base is.

>as is the lack of a supported plugin API (with which I could solve many of my own problems).

I don't know if this would solve your problem, but you can tell Xcode to compile (or maybe handle is a better word) any type of file with a script. So if you want to compile your Haskell source with Xcode, for example, just go to the target settings, click on the "Build Rules" tab, and add a rule that says "Process files with names matching: " *.hs, and Using "Custom Script:" with a pointer to a script that runs the input file through ghc, or whatever you need.