raditz: Basicly if you are fighting/been attacked by a druid you would want 1 spell set and if you're fighting a barbarian/been attacked by a barbarian you would want another.

Would it be possible to make spell sets that could be preset for each class?

It would make it much faster for players to attack different classes and make PvP a lot better as you are constantly prepared to fight any class that decides to attack. Giving you the best possible chance of victory at all times