I considered this the other day. It would be interesting if there were siege maps where you had to stay alive for 12 minutes vs a horde of AI. The settings could be varied, like defending a village from AI bandits or a castle from AI invaders. You get 2-4 lives and the respawn. I'm not sure what the capacity of AI players are for multiplayer, but it would be really cool for cRPG as another means of grinding xp/gold. Maybe you get gold/xp per kill count? Plus a bonus for how many lives you have remaining.