Anyway Eclim seams to be a very special and somehow confusing example of melting together a common IDE with a common editor instead of emulating.

Do you rather mean that products should have UI compatibility modes for common editors?

Many projects assume that emacs and vim keybindings are the two "lingua francas"¹ of editing.

E.g. Komodo edit has "Vi emulation" and "Emacs keybindings"

Or emacs has various vi-emulations like vi-mode, viper-mode, ... and CUA-mode to emulate windows copy&paste behaviour.

That's what you mean???

FOOTNOTES:

(1) this standard is also reflected in bash and readline offering. From `man bash`:

By default, the line editing commands are similar to those of emacs. A vi-style line editing interface is also available.