Kobold/gnome: I'd like to see a kobold or another small, quick moving humanoid. It would make an excellent early game opponent that does not do too much damage. It could still be very useful later in the game. He could approach the party from behind, steal some important object and then run away. Remember how annoying shrak torr was? Now imagine the same level of agility, but running away from you. You'd have to chase him down to get back the key he stole. Also, he could be a nice NPC. A slimy, shady character that would sell his mother if there's a profit in it.
Mantis/grasshopper: There are insectoids in Grimrock world already. I wanna kill one! Insectoid is really a very capable concept, because there are many different bugs that we could possibly see in the game. One type is a tough bettle with exoskeleton (like Emile's warrior. Very resilient, strong, but rather dumb. Another possibility would be a mantis or grasshopper. We all played 2x2 fight dance too many times to remember. What if the grasshopper could dodge sideways? How many times did you run away from a fight looking for an unobstructed 2x2 field to circle your enemy? Now you'd be looking for a tight corridor.
Creatures working in teams: We could have two species of creatures working in pairs, that could compliment their abilities. Here's an example. You have strong, slow moving creature, similar to Tolkien's ent or big herder, that can bind you in place using its roots. On its own, it would not be challenging. But there should be a swarm of fast moving creatures that try to surround you. Normally, you'd keep moving around, but that ent could foil your plan really quick. From the implementation perspective, this doesn't require any inter-AI coordination. AH, you can start breathing again now
Golem: I'd like to see a golem or other mechanical creature. Perhaps an improved warden? This creature should be resilient to throwing/missile weapons, due to hardness of its armor. Possible interesting twist: the projectiles should sometimes hit, but sometimes bounce back.
Different ranks of the same monster: I'd like to see more variety of the same monster. As I understand the modularity in LOG2, that won't be a problem. There are tons of low level skeletons that each look the same. But there should also be occasional higher rank skeleton, with better weapons, taller, moving a bit faster etc.
Beholder: I'd like to see a creature similar to beholder from Eye of the Beholder series (the last one here: http://stanislavs.tripod.com/games/eob1mons.htm). The unnatural pale skin, together with lots of eye staring at you with hate should give you shievers. That creature should be almost completely resistant to magic. I strongly believe that immune creatures greatly enhance the fun of combat as player needs to adapt his fighting strategy to a specific opponent.
Sunken creature: Can we have a half-sunken level? There could be a creature that swims under it and is comuflaged well (only small antennae sticking out, eye on stalks, or something similar to a croc that sticks out only top of his head out of water). It would give the player uneasy feeling of constantly looking out for hidden danger. Of course once the monster gets close by, it drops the camouflage and attacks. There was such a creature in an old game called Dark Forces in a level that was a mix of a swamp, sewers and garbage dumps.
Dismemberable creature: In LOG1 the opponents are fully capable up until the last blow that kills them. That doesn't sound too realistic. Monsters should lose capabilities during fight. For example, skeleton could lose his shield and become more susceptible to attacks. Poisonous shak torr could lose its sting and not be poisonous anymore. For extra fun, you could put some blood stains on the wounded monsters. It would be cool to see that ogres have green blood.
