I'd like a feature to set the PCs to be controlled by AI in combat -- the hardest AI difficulty in the game. Also an option to only possess one or two monsters during combat, while the rest remain controlled by the AI.
Can I ask you in which case this could be useful ?
Yes, you may. Go ahead and ask.
GMAddon1: Adds almost every single monster and NPC from the main campaign into GM mode, plus a few large custom maps to use in GM mode.