New defense: Troop bunker/garrison
The Bunker is able to house troops that you train yourself. But can only be used for defense.
The bunker is similar to your clan castle but with two major differences.
You supply the troops yourself, and they only deploy when you are being attacked.
the housing limit is the same as clan castle and it upgrades in likeness with the clan castle, its deployment radius is equal too.
The bunker would be available after Th7 upgrade and start off with a housing limit of 10. And increase 10 housing space every upgrade until 60 total housing space, same as clan castle.
i don't know if this has been suggested before, and have read stickes and did not find the idea ruled out.