Regardless of if people beat it or not, you're still farming 6 items a week from the more easily beaten Turns (1-4). At that rate, with the RNG of the drops included, you get more bang for your buck from Mythology at 300 a week. It's pretty sad that my best way of obtaining gear is through tokens I can get from a dungeon I can beat in AF instead of the dungeon that less than 100 people will clear by 2.1.

By and large the main reason that people will have difficulty clearing Coil is not because it is too hard but because it takes awhile to get everyone the right amount of HP.