NppFTP is a very good tool, but still does not support scp properly, and using public/private key authentication is still a struggle, or at least I cant get it to work. I use it at home for certain servers, but at work I prefer WinSCP and NPP when not using vim.
I hope this thread will inspire some plugin developer to integrate shellcheck into a plugin, have some kind of line highlighting or popup/tooltip type popup showing the output of shellcheck validation, maybe even a autoreplace text, which needs to be used with care :-)