First off. Geffen is very valuable for its dark pries spawn and Black Rosary drop... Especially in those dangerous times where magic is your main enemy. As for Payon, agreed, nothing of value in there aside from Abyss Hall of course.
So Vellum Weapons were removed, Siege Set was removed, Supply Boxes were removed and WoE Pots were removed. Godlike materials are removed. So basically everything was removed that made WoE so rewarding for its participants.
Lets analyze the rewards. Godlikes materials is a no brainer. Insanely strong gear, some are BiS. Siege Set was removed because, just like Godlikes, it was too strong and pretty much BiS for PVP. Vellum weapons were partly BiS or utterly useless. The Pots were unbeaten by anything else. In other words, the games strongest gears, or parts of it were removed. (Atleast for PvP/GvG)
Now to re-balance it. We would need to offer something that is valuable enough, but not as broken as the disabled items.
My ideas:
The guild treasure room always spawns 2 types of treasure boxes. One with common consumables. One with gears and rares. This is how it works on officials atm. Example: Payon Castle 3. Monster ID #1348. (Consumable/Common Chest). Monster ID #1349 (Rares/Godlike Chest)
This system is a good base, but the rewards are extremely outdated and poorly designed by gravity. First off, youd need a high investment level to even get anything useful OR something that benefits ALL of your guild. In other words, if you open 2 chests and get 1 OCA, 1 Berry, 2 Oridecon and some Dumb Item no one uses anymore, you basically get nothing. Sure you can open this chest 7 times a week, but that doesnt really help. If you have a guild of 20 members, you cant really reward them with something like this.
So first thing would be to REMOVE all useless items in the treasure chests were going to use and replace those items with something that is of actual use in modern RO times. I am not saying, replace "Chainmail" with "Nidhoggurs Shadow Garb". I am saying something like replace "Chainmail" with "Upgraded XYZ". Instead of single items, we should have boxed stuff drop. A Rare drop could be a "Box of Fish Slice (7)" or something.
Next idea would be to still have treasure boxes spawn in Hall of Abyss. (The Killable ones) Instead of Siege Weapon Supply Box, they now drop a Upgraded Box, which gives a random Upgraded Weapon for example. Could also use Lvl 4 weapon box that include current good items. Such as Combat Knife, Ice Pick, Weapons from Strongboxes.
Another idea would be to include Strongbox Keys or Unlocked Strongboxes into castle drops.
kawaii coins/ leika coins are also an idea worth mentioning, but need to think about long term. Dont want the donations to starve out because WoE generates too many. Kawaii coins only would be an idea.
If possible, have a script run during WoE. Any active/non idle/single IP player inside castle once WoE ends should get something for their troubles. Winning team could get something extra.
The idea is not to overpower the winning guild, without having trivial rewards no one wants anyway. We want to reward everyone for joining WoE and burning their materials and pots, but make sure the winners are the ones who take the trophy home. Long term, we want loyal and active PVP Guilds who display superiority to be rewarded for their troubles.
Investments should be global for every realm, increased cost. Unlocking Level 1 and 2 or SE Guild dungeon access. Hall of Abyss for Castle holders only. Castle holders of castle 1 and 2 have access to both Hall of Abyss maps (or just one, if merged). PVP enabled on Hall of Abyss. Guild dungeon pvp could be enabled aswell, or disabled, depending on player feedback.
Have one Huge ass map, if you decide to merge it. And either have every relevant monster spawn on that map. Or give players access to all guild dungeons at once, as soon as the investment reached the required treshold.
Current Most desired items in the game: (No instance related)
Cash Points (Thx to cash shop having 2many valuable items)
Kawaii Coins (High Headgear cost with not enough ways to gain, no item exchanging/crafting)
Strongbox Keys
Strongboxes and their rewards
Classic Endgame MVP drops, because of MVP power spikes. (Variants, Nidhoggurs, Bio loot)