Alternatives

I've contributed some nontrivial patches to Emacs and was in the past a core committer.  Don't
get me wrong, Emacs is great and has left a lasting impression on me.

However, while it makes sense to have a good relationship between one's interactive
shell/toplevel and one's editor, I don't think it necessarily makes sense for them to be the
same thing always.

Emacs' fundamental architecture at this point is just too limiting; Emacs Lisp is far behind
the times.  The buffer-oriented display technology lets one easily do some neat things and
lends itself very well to a keyboard-oriented control (which is crucial for a good
programmer's editor).

But Emacs doesn't have anything like GtkTreeView.