Feels like I'm spamming every comment within this article, but this is exactly what Ensime is for. I hope that Vimside (http://www.vim.org/scripts/script.php?script_id=4298) up to date which addresses most of the above.
I don't think it would be too hard - mainly the server startup has been tweaked so you dont embed Ensime.
Neovim is also interesting, I understand they have a much nicer plugin architecture as well.
I'm really hoping that someone uses our recent work on Ensime to bring vimside back to life. Hopefully provides a lot of the 'missing' features that vim (semantic/type info), accurate completion etc. But its going to require a Vim expert to step up and fix the integration.
We did - hopefully you enjoyed it. We are talking with the maintainers of the sublime plugin to bring it into the ensime org and I'm trying to a vaguely working version out in the next few days.
