Thanks for the feedback! So we do have some things in the game that show when towers are supported, though it's not as obvious as we'd like in a final product. For instance, the archery range does not have the archery targets on the wall until you place a military structure by it. Or the outpost doesn't have the lancer guards unless it's on the edge of the kingdom and next to a resource tile, etc... But we do plan on redoing the highlight system and having more obvious visual effects for what structures are being affected by another.