Ran the Water Rank 4 Accessory Quest today with my Water team and had more resists of Affliction resistance down on Mordred (4x) than Cthulhu's DEF debuff (1x with 3 stacks of affliction rate up). Affliction rate up seems to make a very noticeable difference, making previously unreliable debuffs fairly reliable. I now have 8 affliction rate up accessories, so I should be able to loadout pretty much my entire team with them.