I can only imagine the kind of fascinating, or maybe frightening list of perceived requirements someone might need from their editor/ide that boils down to their installing this.
Major visual difference would be that whatever the editor font settings dictate, would apply to all the UX not just the text-editor tabs. But that, who would even mind.
The extensions compat would have to be NodeJS-based I guess, but the rest wouldn't have to be written in JS/TS I suppose..
Plenty of us are "happily Stockholmed" by the overall DX of VSCode but were there a Electron-less but otherwise 99+%-compat-and-keeping-up-with-vsc rendition (TUI or native GUI), we'd jump on it nonetheless.
Me, I first wrote programs in AMOS Basic, which was certainly not CUA either (I remember shift-backspace erased a whole line, which could be really frustrating). I've done enough learning of tiresome nowhere-else UIs... back when I played Nethack, I would of course insert a big S anytime I tried to save in another program for a while. Nethack was at least fun enough to make it worth it.
VSCode is fast for stuff I do in editors which is slow elsewhere (thanks in no small part to Mr. Gallant!) and better at doing anything an IDE used to do, than most IDEs. Does vim support full-featured language servers/tree-sitters these days?