I agree with you that vi is lighter than vim. I’ve seen more than a few instances of an OS just aliasing vi to vim.

On that note, why are the keybindings for vi on a “modern” Ubuntu different from fedoras? I remember having to mess with ^H in a vimrc or something to that effect to mimic the behavior I was expecting.

Sounds like the terminal (not vi) you're using has different defaults; backspace and delete are the two common keys that vary.