Another idea would be to treat weapons and armor and other things like ungatherable resources. Using the barter mechanic already in the game, you can convert wood and metal at the Blacksmith to spears, swords, chain mail, etc. "resources" which are then added to the player's stockpile. Hoplites then don't cost "50 food and 50 wood", they cost X amount of spear resource and Y amount of shield resource, etc. and -Z food per minute.
At the corral, I could see converting the Food resource into the Horse resource, so that cavalry also cost an amount of Horse resource.