It doesn't make sense to me at all for players to be able to buy upgrades to the Keep with Gold, and for attackers to have to buy their advanced rams and potions with ordinance.

Gold grows on trees. Guilds have a ton of it. 

Ordinance isn't gotten as easily, and it requires so much of it to get a little out of it.

Either make both items cost gold, or make both items cost ordinance. Because right now, people are buying upgrades with gold knowing that players don't have enough ordinance to buy the improved rams / oil potions. Keeps are stupid difficult to take when the door is upgraded yet your using the same old ram.

The system just doesn't make any sense.