MacPorts current vim is 7.4 and the version shipping with El Capitan is 7.3.

So…

$ sudo port install vim

then

$ cd ~
$ vim .bash_profile

paste in:
# Use the up-to-date MacPorts vim
alias='/opt/local/bin/vim'
# Life is good, so is vi
export EDITOR=/opt/local/bin/vim

you’re done. Consider portsUpdate to keep it up-to-date daily.