So we've all seen the various revolutionary new schools, spell types, and how they have changed how battle works. So let me attempt to suggest another. Counter spells.
How do they work? Unlike other spells which do their effect when cast, these counters will only activate after the certain requirements are met, and they are primed. They seem more like a mine, than anything else. You have to cast the counter first and then a requirement needs to be met. Each counter has a different effect, depending on school. Counters work similarly to auras in regards that they have a round limit, but they can be used with auras active. Blades, and traps are not activated when a counter activates, however shields will. Counters can be cast on anyone, depending on the activation requirement. These kind of spells would most likely be gained via school quests or some secret trainer at a high level. Counters cannot be stacked on top of each other and will erase the previous counter applied.
Examples: (Assume they target allies unless stated otherwise) - Activates on incoming damage. Deals 50% of the damage taken to the attacker. - Activates on incoming trap or negative charm. Stuns target and gives self a -20% universal shield. - Activates on incoming damage. Puts a 1000 + 500 DoT on the attacker. - Activates on incoming heal. (Targets enemies) Inverts the heal so it does damage instead of healing. - Activates on outgoing heal. (Targets enemies) Heals enemy for full, but you gain health equal to 50% of that heal. - Activates on incoming ward. (Targets enemies) Cuts the ward(s) in half and gives it to yourself. - Activates on any incoming dispel. Repels the dispel and deals 500 damage of the dispel's school to the attacker.