Clan avatars. This is an RS gold enormous amount of work with very little reward. It's not much. Battlefields. They are fantastic tech however, is anyone actually using these games? If someone wants to fight then they head to Clan Wars or the Wilderness. Battlefields are more likely to be one-sided, or simply bizarre.
It is also worth considering the fact that, apart from the xp gain, a clan citiadel does not do anything for you in Runescape. The cape of the clan is decorated with three stars, while the vexillum contains fireworks. What is the point of it? Your cheap RuneScape gold citadel is never ever visited by anyone other than members of your clan.