I think it would be more fun if the game had a crafting mechanics, where pieces of legendary shards of a certain equip is obtained through hg runs. The he higher your luk stat is the higher the chances of the shard to drop is. It would facilitate a need for a luk type hero it would make hg runs more interesting. Now that hg gives us so much essence we can midigate a over abundance of them by having the craft system require a certain amout to be used to make the equips, similar to getting 5 star story heros. You can even have the craft system to award a random extra boost in a random stat to make sure that each crafted equips will be different but still more valuable than the ones you can get from chests. Just throwing ideas, you can even have a rune system to where you can enchant the equips with certain types of stat boosts to further the variation between equips.
Thank you for the suggestion!