http://stackoverflow.com/questions/1663627/guile-and-emacs
That's 15 years of talking. My personal feeling is that sometimes it's just better to abandon projects that stagnate. There's an open source Go version of Sublime, for example. It would probably be easier to maintain.
It has reached an odd place, there is enough legacy code (or so it's believed) that it can't be abandoned, there are clear innovations that will never go in to elisp (jit compilation, threads, Ffi, etc) and guile isn't being accepted while it is clearly the best way forward that has been suggested. It's like emacs is done.
Considering something else only makes sense...
As with any corporate product, you can't go changing shit when you have a large paying userbase.
That's throwing the baby out with the bathwater. The only thing which makes Emacs-on-Guile difficult is backwards compatibility. If you find Sublime a viable option, then compatibility isn't an issue for you; in which case there's nothing preventing you from using Emacs-on-Guile right now.
That said, there's a lot of information here that's very useful for the starting Elisp programmer.
I don't see how these are evidence of the author having "CL background". CL is pretty much identical to Emacs lisp with regards to both of these things.
Since 1996, Emacs was a kind of IDE replacement when I was in UNIX environments and could not use my beloved MS-DOS/Windows IDEs, but nowadays UNIX systems also enjoy quite powerful IDEs.