Eclipse's uses XML to declare UI, behavior, expressions. Completely baffling. Terrible docs. Extremely difficult to debug. I was reduced to trial and error (after copying working examples I found).
I've used Eclipse since the early alphas. Its muscle memory.
Scouting the plugin dev stuff of IntelliJ, it doesn't appear to suck so mightily. I've forced myself to start using IntelliJ.
I miss LISP so much I could cry. Even so, I remain wary of metaprogramming. And I very much want to do plugin dev, vs modifying the runtime, for the separation of concerns. I've had to customize all-in-one runtimes and borking the whole runtime with a bad override is not fun to debug.
I've not done emacs plugins, so can't comment or compare.
Your concerns are artificial! Let go of your concerns and be free. The hundreds of Emacs users around the world are already doing it. It's great.
It used to be a bit of a wild-west without lexical binding but we have that now and it's going over pretty well. Fewer libraries step on each others' toes as adoption spreads.
We have package management built-in. We have awesome introspection and debugging tools. There are a lot of wonderful built-in packages.
My init file isn't even written in raw elisp anymore. I use a well-documented org file. The amazing org-babel library is bundled in. My init file is written for humans to understand and only incidentally for my editor to execute. It's great.
I only wish more software was designed this way.
Came here to say that I do this, too: https://github.com/nhoffman/.emacs.d
Not sure if it was worth the effort, but it was fun!
http://sachachua.com/blog/2012/06/literate-programming-emacs...
One interesting library I've come across is skewer-mode. It depends on a package that implements an asynchronous web server to inject some handy javascript into your browser that opens up a two-way channel with Emacs. I just have to add the href to load the script in my file and then I can open up a javascript REPL in emacs and load code into my browser without refreshing or anything.
I've heard of projects that let you programmatically embed and control webkit instances.
I publish books from emacs.
It's a handy programming environment and not merely a single-purpose application.