I think this is the crux of the issue with a lot of plugins.
For my personal preferences, when I start with a new language I just want to be able to build the simple “Hello World” file from the editor. I code a little, build, change, build, change, etc. It is a conversation with the compiler and I don’t want to have to leave the editor for this. I view this functionality as a MUST for absolute beginners. When I was starting out, this was the reason why I chose SublimeText over Atom. I could not figure out how to make Atom build on demand.
In my perspective, the syntax highlight, elm make and elm-format belong in a single “Elm support” plug-in. The only configuration for this plugin would be the elm-format on-save toggle which could be false by default to not confuse absolute beginners.
The problems like bad performance, battery drain and fighting with the autocomplete come ONLY when you bring in project analysis. That should be delegated to an advanced support plugin.