At the moment, if you are fighting anywhere except Coil, you will have 95% hit rate when you are completely naked against targets of equal level. You will only need 1-2 pieces of level-appropriate accuracy gear to reach 100% hit rate.

Coil requires between 460 and 470 accuracy to reach 100% hit rate for the whole dungeon. The requirement is lower on turn 1, but it ramps up as you go deeper.