That's what I've been doing in my mods. Will continue to fine tune it. Between Toughness skill, certain combat arts, and items, a vanilla character can reach 100% damage mitigation for all types.
I've decreased the mitigation granted by Toughness as well as the item modifier "sb_def_damping_any". I'm considering going a step further and allowing only 2-3 channels max on a single item, with the full spectrum only granted on Legendaries or as a set bonus.