I often use visual selection mode in vim so that I can see what I'm about to operate on. For instance, if I want to change text between the cursor and the next match of a regex, I want to see the selection before I change it. So instead of c/re[enter], I type v/re[enter]c. It's one extra character, but it saves me a lot of headaches. This is the first I've heard of Kakoune, but I'm definitely intrigued.
Probably too late for anybody to see this comment, but I'd just like to drop back in and say I've tried it and it's amazing. I really did not expect that another text editor would be able to improve on Vim on basically all fronts, but kak has done it.
