You're right that changing the whole editing model will involve rewriting a lot of keybindings. You could do that in vim if you really wanted to -- start by remapping motions to enter visual mode first. I don't really know why you'd want that when visual mode is already a keystroke away, but that's ok.

FWIW though if that's what's important to you, I get the sense that kakoune is much more vim-like in making it easy to compose with other tools, while being set up for your preferred editing model.