Nice idea though doing this is likely to stop game dev since the players can take over and the dev has no incentive to continue even though some things will be beyond the player's ability to mod. Has happened before both successfiully and not, but it takes years before a game has enough momentum with modders to be maintained by them and if they don't it's "bye bye"... just look at the fall off of Minecraft and Starcraft (and the "devs" didn't even abandon the moddable version of Minecraft, "allegedly").