I very rarely use autocomplete on Emacs, except hippie-expand. I have yasnippet installed but I have never used it. I just checked, it's not even key bound to anything.
I work on greenfield projects so I see my fair share of boilerplate, but honestly, it's just a minute part of work that's almost meditative to write a little bit of trivial code (i.e. a function signature) in between sessions of hard thinking. Writing boilerplate is very far down the list of things I seek to optimize.
Company? Helm? Whatever vi uses that's like company and helm? Haven't IDEs written function calls for you for like decades now?