Just so I'm completely clear on all this now...
So the one ring does not "prevent" the wounds. BUT in a case where wounding the ringbearer is a cost for something, IF you use the ring to "convert" to burdens, you technically aren't paying the cost, right? I'm sure I've seen this happen with a Brute, but I just wanted to make sure 
Whether you convert the wound with The One Ring, or prevent the wound using another card, if you aren't actually
taking the wound, then you aren't paying the cost. With a
Morgul Brute situation, you have to actually
take the wound in order to prevent the burden.