Also, I haven't written much go, but my general impression is that the language trends on the verbose side because of the lack of things like generics and it's error-handling strategy, so I'm not too surprised that it's more pleasant to use an IDE for go than it is to produce it manually.
Also, most of my side-projects are in Common Lisp and, I've yet to find a "mainstream" programming environment that's more pleasant to work with than my SLIME/emacs setup for writing CL.
Even basic things - ability to see all callers, all available methods, warnings on bad constructs and yeah, templates for often needed sysouts ...
Refactoring. Oh just a simple thing, like simplest of all available refactorings, rename something with zero worries about forgetting some place or changing one more ... I missed this ability so much ...
Also, depending on the language, the tooling in Emacs can get all the other IDE features you are talking about: for haskell there's ghc-mod + intero, for common lisp there's slime, etc. if you install the appropriate plugins and then use something like Syntastic/Flycheck, you can have all the nice editing abilities of vim/emacs as well as most of the useful parts of an IDE's language support.