My statement about the lack of uniformity was in regards to several issues I had with some plugins in emacs. Even my friend who codes his own plugins for emacs was of no help because 1) there is too many approaches and dependencies to write plugins, 2) there was no solution. Also, there are too many plugins to serve the same purpose and I found it difficult (compared to neovim) to figure out the difference between them. At least twice I also experienced conflicts between plugins. Finally, the level of customization was also less granular than what offers neovim. Again, I can see why emacs is appealing to some. It’s just not for me. As I like to say, the number of options available in the Linux world is one of the most beautiful things that makes this OS the only one you can tweak perfectly to any user’s needs and preference.
I would add that neovim and emacs both have a steep learning curve but I personaly found the level of support and core and plugins documentation for neovim more accessible, readable, and better organized.
I completely share your vision about what an IDE should be doing. I’m old school and adhere to the “do one thing but do it right” philosophy. Also, I hate relying on one tool for several needs because if anything goes wrong it has multiple impacts. As a side note, I use neomutt as my email client and you can nicely couple neovim to it to write your emails ;)