Emacs might actually get away with switching to CUA, it's already halfway there - you're always in "insert mode" and use Ctrl/Alt+letter for advanced operations. But rejiggering Emacs's shortcuts will alienate current users while probably not attracting many new ones. This is always a problem for a minority-use product - your users don't want to use "standard" software for whatever reason and just blindly chasing the majority will have you fall between two stools. Vi(m) probably can't be built around CUA principles. Its modal editing language is completely alien to what CUA is and while you can add a few bespoke shortcuts (I used to have ctrl+s for save), they usually stick out like a sore thumb (I switched to <leader>s because it was more natural). I would love to see someone try though, it might work out.
For the second point, I'm inclined to agree that we should be able to show information in a better way than a pure text buffer on screen. There are neovim shells built around Electron which I'm keeping an eye on, because those should allow for rich GUI controls to be easily created. Though it might actually be better to adopt something like Tk in vimscript to give plugins a very simple way of showing GUI components.
Parent was very rude, but they do raise the correct point that our editors were built in a different time and we could adopt modern principles to make them better. VSCode is probably this generation's Emacs.