Yes, you can do all of those things with sublime's API (https://github.com/wuub/SublimeREPL, https://github.com/SublimeText/Origami). Yes, emacs is more extensible, but not where it matters, really. I.e., I don't think you're going to see any cool feature made with elisp that can't be ported to sublime.
Ok, that's pretty cool. Still doesn't seem as supported by the core APIs though. In Emacs I can run a REPL and attach it to any process with a few lines of code.
I love Sublime Text, but I would argue that Emacs is more extensible in all sorts of places where it really matters.
You can probably add every single feature in emacs to sublime. The 30 earth-years and many, many man-years of features, additions and smoothing of interactions that has gone into emacs, will however take quite some time to come to par with.
See e.g. tramp, org-mode, the vc-modes, gnus, magit, smart indenting etc.
martinced: you have been hell-banned for some, to me, completely opaque reason.
Genuinely curious, but I think you can do a lot more with Emacs' APIs, and modify core parts of the editor since most of it is written in ELisp and you can easily swap out functions.