Truly, the future belongs to the crowd–though some would argue that modding has become become sanitized. It's hard to dislike a developer that's willing to give out modding tools to its players though.
So! Good news, Total War: Shogun 2 fans. Creative Assembly launched Shogun 2 Steam Workshop tools, which you can check out here. There's maps and mods to download, so get to it.
PC Gamer reports that in addition to this, there's an update map editor and a new Total War wiki that's meant to serve modders. And remember: Total War is on sale on Steam right now.