I agree, I've fantasized about an editor with a truly pluggable editing model which is decoupled from the other parts.

Yi was kind of designed like this, I believe. You could compile in an emacs-like model, a vim-like model, or presumably make your own model.

I've used Helix and Kakoune in addition to Emacs and Vim, but dealing with the limitations/featureset/plugin treadmill gets a little tiring.

I have been following Zed, and it seems that they have rearchitected things to enable adding Helix mode and making the editing model a bit more modular, but it's still fairly new. They are fixing bugs pretty quickly. I will have to try it again.

They have a nice discussion here:

https://github.com/zed-industries/zed/discussions/6447

They reference Ki, which also looks cool, and they out some of Helix's inconsistencies in their comparison: https://ki-editor.github.io/ki-editor/docs/comparisons/

I prefered Kakoune to Helix (it was more consistent). But to your point, being able to swap these things out more easily would let you choose an editor based on features, and not tradeoff between features and an ergonomic editing model.

Ironically you can use Ki inside of VSCode (and I know you can use Vim that way too), but VSCode is so darn bloated and slow...

The truly pluggable editor is emacs. I too spent months trying out neovim, then emacs, then finding helix. Spent a year on helix, then zed because I would rather have something more complete, and brought with me all i could of helix modal editing.

But emacs. Emacs is the one that can truly become anything you like. And with lsp and treesitter being finally in it. I've finally came to my senses and started building my helix in it.