WTF are you talking about? Vim have may have many demerits but segfaults is not on that list. If segfaults are that frequent you described then people would have jumped ship already.

I can't comment on the code structure of Vim but it does not matter to me because end product is working fine for me for 5+ years. Also bad code structure did not stop continuous development of Vim. Just for example there were 1000 patches added to the core before Vim version was changed from 7.3 to 7.4 within 2 years. Important features like more python binding, lua bindings were added during this time. Even if you see the current patch log of 7.4 ftp://ftp.vim.org/pub/vim/patches/7.4/README 68 patches were added since 7.4 release.

Though async future is not built-in there are several plugins for doing async operation, for example vim-dispatch[1] and vimproc. Vimproc is more widely used. See Unite.vim[3] , neocomplete[4], VimShell[5] for demonstration. I would specially point to VimShell because with the help of it you can run REPL inside Vim and pass buffer content to it. Also there is YouCompleteMe[6] which provides FAST autocomplete.

[1](https://github.com/tpope/vim-dispatch/)

[2](https://github.com/Shougo/vimproc.vim/)

[3](https://github.com/Shougo/unite.vim)

[4](https://github.com/Shougo/neocomplete.vim)

[5](https://github.com/Shougo/vimshell.vim)

[6](https://github.com/Valloric/YouCompleteMe/)