Thing I would like changed is usage of ultimate skill for Schoolarsages. It's not good when ranged character has to go in the middle of enemies to use his meteor shower. Targeting would be practical, as it would enable him to stay in the backlines (as he should) and throw it all on the enemies.
I would like to point out that Boss in Valthiria's Victory quest is little bugged (for me): the Area of Effect for his chage-up skill is shown smaller then it really is, as the damage goes futher then Arquebusiers' max attack range - which is, in turn, larger then the boss' attack's indicator range.
Also - as mentioned before - it would be good to be able to change the order mechanic in battle - having 3 people walking behind is nice, but it would be even nicer if you could tell them to stop and move only the leader. It would add more deph into the game, where even weak parties would be able to deal with monsters by leading them into traps and the like.
New class would be appreciated, like Trapmaster (goes up from Scout class). He'd be about preparing for battle beforehand and making enemy go trough the traps in order to ensure victory.