Just an advice: until the NPC AI pathfinding algorythm is as it is now please DO NOT MAKE MAPS LIKE THE FIRE CAVES.
Or if you'd like the players to be tortured at least build in more respawn points. It's a bit irritating to find my idiot NPSs in the lava after every second catwalk and when commiting suicide to respawn my party I have to run across the whole stupid map again and again and again.
Of course this way you can make REALLY long missions. I mean really long... to the point when a player just gives the middle finger and drops it.