"Extreme" is an inaccurate term. If you don't suck at the game and you roll, you could be naked and still have an advantage over the average souls player. This isn't a game where you tank hits unless you're wearing super heavy armor. A little loss in defense doesn't matter, no matter what research that one guy did showing the drop in defense percentage. It really isn't that important. Trust me, if I can beat the Nameless King without wearing a helmet, he'll be fine.