Do you want a radioative feature, like the feature in Fallout? I would need to create a body object for the player, so that parts of the body could randomly become more functional or useless by mutations.
I'm currently working with a 20 * 65 map size; would people want larger map sizes?
What about a worldmap feature, like in ADOM, or would a Dungeon Siege no world map system be better? What about magic teleporters or space age beamers?