When I was at uni and I logged in from home with my 1200 baud modem, I used vi's "open mode" (no, vim doesn't have it), which is visual mode, but restricted to one line at a time. I even had a shell alias for "ex +o $*" to start it. It was quite fun to use, but nowadays it's not terribly useful anymore, so I can see why vim hasn't implemented it.