Many things requested are available in emacs.

> However, I personally don’t use this capability of shell a lot: 90% of commands I enter are simpler than some `cmd | rg pattern`.
> (kbd "C-c") doesn’t work as it works in every other application.

So rebind it? Even terminal emulators allow for rebinding of keybindings, and so does emacs.

> I launch GUI version of Emacs: the terminal one changes some keybindings, which is confusing to me. For example, I have splits inside emacs, and inside my terminal as well, and I just get confused as to which shortcut I should use.

IMHE the solution is to decide which tiling manager you wish to you use (my experience is informed by using i3 to tile and sometimes emacs). 99% times I use my i3 to tile, and emacs only splits in half (C-x 2 or C-x 3 depending on what I need and how wide the emacs window is)

> Why can’t I type cargo test, Enter, exa -l, Enter and have this program to automatically create the split?

What you are looking for is `cargo test &`, `fg`, `bg`, and (kbd "C-z"), no? The ability to suspend and bring to foreground or background enables this kind of 1. run tests 2. list files. My own experience suggest that how I create the split is dependent on some, potentially implicit, context.

> Additionally, while magit awesome, I want an option to use such interface for all my utilities. Like, for tar?

Firmly agree, and I believe this is what the transient[1] package is for.

> extensible application container, a-la Emacs or Eclipse, but focused for a shell use-case

Emacs /is/ focused for shell-use case, at least in my understanding and use of it.

> A UI framework for text-based UIs, using magit as a model.

ctrl+c, ctrl+v and friends should work as expected.
cua-mode enables the "normal" copy and paste bindings.

> A tilling frame management, again, like the one in Emacs (and golden-ratio should be default).

What's wrong with `C-x 1`, `C-x 2`, `C-x 3`?

> A prompt, which is always available, and smartly (without blocking, splitting screen if necessary) spawns new processlets.

Isn't this what M-x is or would it taking up the bottom line disqualify it for "splitting". Regarding blocking, I do agree it's very annoying to have emacs become unresponsive.

> An API to let processlets interact with text UI.

I would assume that there is something lacking from emacs lisp api[2] for manipulating emacs, but it's not clear what they are from this authors perspective.

> A plugin marketplace (versions, dependencies, lockfile, backwards compatibility).

What is wrong with melpa, quelpa, emacs-wiki, et al?

> It doesn’t define out-of-process plugin API (things like hyperlinking output).

It sounds like that would require the out-of-process layer (shell) to be as expressive as the in process layer. For instance, emacs can link to files, and new custom link styles, but my terminal is loathe to support http(s)/(s)ftp, and I presume is not easily extensible (as emacs) to new protocols.

> Its main focus is text editing.

Everything already communicates in text, it's not clear there is a obvious alternative or what would suceed text editing for this use-case.

> Its defaults are not really great (fish shell is a great project to learn from here).

Perhaps, but the gnu emacs community seem to profess a "we-came-first" mentality for conflicts with emacs defaults and the 'wider computing experience'.

> ctrl+c, ctrl+v do not work by default, M-x is not really remappable.

cua-mode and false, I have m-x remaped to use helm.

1: https://github.com/magit/transient
2: https://www.gnu.org/software/emacs/manual/html_mono/elisp.ht...