IIRC, ACC was added to healer gear for hunts. Elite Marks require a higher ACC cap than regular enemies and SE decided to give healers some ACC so they could solo them (especially the B ranks which are now and originally were meant to be solo'd). That's why the new gear has no substantial increase in ACC; Mark acc reqs are still the same.

Basically SE is only going to assist with open-world content. If you're so adamant about DPSing in Coil then meld some accessories with ACC and upgrade your relic with it.