I am using fish 2.1.0 and Escape is not considered meta.

This is really annoying, especially on OSX. You could configure iTerm to make 'alt' behave like meta, however, and I quote fish website,

configuration is source of all evil.

Bash, zsh, emacs, and many more support out of the box Escape as meta, which allow a proper usage without having to temper with the terminal configuration.

I understand why Fish is not POSIX, however, I don't see any argument why this should not be supported.

After discussing on IRC, it seems that it IS supported. However, it does not work on OSX with terminal, iTerm2 or with direct TTY within virtualbox.

Is it a bug? Is it expected? If yes, how could I work around it to make it work?

And please, do not tell me to configure my iTerm. I want to use Escape, not Alt.