So from playing and reading here it seems like building strong armies is draining a ton of elixir from the game. There is already a defensive bonus (ha!) when you clear the headstones after a defense. What about making this proportional to the troop cost? Maybe one-third or something. And having headstones only appear if you win the defense?

This would recycle a good part of the elixir being spent, rather than having it vanish into thin air.