[Cheezeninja]

To me the preferred solution would be making sneaking units targetable by overland spells. While hoarding would still be quite possible, useful, and smart to do, an enemy with good and detailed intelligence could attempt to take out your production base.

I would also very much like to see an overland spell capable of castle destruction, which would open up some very interesting tactical opportunities IMO. If you made it so that the chances of success were predicated on the number of earth gems put into it against the defense rating of the castle it would also encourage people to use the high defense castles alot more.