LUA Editor please. And the Map editor would be nice too.
Else, the game is getting stale without new fan made content.
Most great games have this stuff, fan made stuff and tons of replay value and adds to the fan base by keeping it alive. (Civ4, Oblivion, etc).
It adds to game sales since the most popular games have full SDK did you notice?
Good Mods = More fun = More Hype + SALES = PROFITSSS!