Haven't really looked at the source, but is the neovim dependence just for starting ranger async? In that case vim 8 support might come soon?

I have a neovim build, but I tried out SpaceVim on it and just went back to a very lightly patched vim since SpaceVim felt too bloated and I've been too lazy to clean it all up.

No. It's more like to implement ranger's functionality using neovim's rplugin framework. Vim8 support would require other framework such as nvim-yarp.

This is a "neovim" storage explorer plugin to bring together the best of Vim, ranger, and rclone. It's called vim-netranger just because I might port it to vim8 in the future. It's still under development, but is already very useful.