1. Single threaded. Stuff like CtrlP or NeoComplCache are running in foreground and you can't do anything until they finish.
2. Lacks API.
3. Very IMHO: vim-script is not an example of good design.
4. No real UI.
5. No embedded console.
6. Plugins don't play nice with each other.
7. Speed.
8. Mixed modes.
Mr. Moolenar and thousands of commiters created a brilliant piece of software, just the problem is that it needs to adopt new features, its time to move on: real GUI, at least some general rework on vim-script, or even completely replacing it (bold), multithreading, centralized plugin repository, better error handling (read error reporting), etc...
One can of course say that VIM stays VIM even in 3013. But I have a hope that once VIM will adopt all those features.
Until then I'm looking for some alternative with support of modes, text objects, navigation...
What I've seen so far:
1. SublimeText2 "vintage mode". Loud. Next fetish after TextMate. To be honest I wasn't impressed that much + it costs money. Money that I wouldn't pay for it. Very limited and inconvinient VIM mode. Not an option.
2. Editra. Slow. VIM with 60(!) plugins is faster than core Editra. Looks like Python2 + wxPython is not the fastest thing one can imagine.
3. Various Aptanta, NetBeans, Eclipse and etc... VIM-emulators. That requires lots of polishing. Also they're slow. Sometimes even slower then Editra.
4. Gedit + ViGedit. Dead long time ago, but looked promising.
Do you know some other alternatives?
P.S. This is a shortened version, full text didn't fit. See here: https://gist.github.com/naquad/5762173