What can a Runemaster do in large scale battles?
This is the same as with group versus group battles. You generally will never want to be the first to cast and AE spell, because you may break a LOT of mezzes with it. It may look great to have a stream of 12 lines saying that you did 90 points of damage to an enemy. But that 90 points doesn’t compare to having the enemy asleep for a minute or more. It’s best to focus on one target at a time and nuke them until they are dead. Just don’t get such tunnel vision that you forget to move!