Some small changes in AI department could help a lot.

For example, have opponents never target "obviously" immune targets with elements they are immune to.
It should be common knowledge that you can not injure fire elemental with fire, or zombie with poison.

Also have them have in-combat memory, so if enemy target someone who is immune or highly resistant to some type of attack, then he or his allies should not target that person with same types of attack in the fight (if they have alternate ways of attacking).

Last edited by player1; 12/10/14 09:53 AM.