Yeah Ryan Hall needs to fight more and he'd be up there.Worth noting that Ryan Hall would actually top these lists- if he had enough fights to qualify for them. He's be #1 and #2 for Str. Def and SApM, respectively.
http://ufcstats.com/fighter-details/8866c6f509c19089
Jon Jones does an amazing job rolling with punches if you watch closely but he’s not the least hittable I’d say Dominic Cruz considering the level he fought at.