I don't know about RSI yet but I do know one thing : Vim workflow is to make a quick edit and then go back to normal mode as quickly as you can. This prevent accidental inserts and you are always back at the command center for your next edit. The same way some people understood most of the time is spent reading code rather than writing, vim's insight is that more time is spent doing edits than actually inserting text. So maybe strecthing your pinkie to the far (but admittedly easily locatable) corner of your keyboard is good RSI exercise I don't know but the Caps lock is just as easy for your finger to locate and don't require strechting. It's just better.