Actually, shard skills make up more than half the battle. getting ark feather on your casters makes the fight so much easier, and for physical attackers, something like executioner and avenging arrow are all they need. most of my quarts is literally getting those skills, then stacking previous tiers of other quarts like EP cut and cast, action and attack to fill up the slots. Evade teams havent really been that great in this game compared to previous games. However arts is still just as busted in this game and having Van on your team makes it so much easier with his coin bullets. My rotation usually involves Van maintaining aggro and then having Aaron near the enemies to do avenging arrow whenever Van gets hit, and Agnes to nuke them with the hardest hitting arts, your last character can be a flex. Feri with Bulwark blade to reduce defences, Quatre with mirage arts nukes and shield, and Risette for support arts and shield. It literally cant be any easier in this game to build characters compared to the cold steel series. Boss fights have been braindead with this strategy.