I'm just spitballin'.
Make clans something.
- Drop the 30k gold entrance method. Replace with an induction method. While the absolute leader of the clan is the leader of the related cabal, put someone else in charge of the actual clan, a cabal elder or vet perhaps. Make characters apply for induction. Require three trusted members or better to vouch them in. After that, automated quests can get them to trusted. Clan elders would probably need the authority to induct new members. This will thin the herds a little bit. And, more importantly, since you cannot easily change clans, there will be an interview and newer players will get in the proper clan. And something freely given has no value. This makes players EARN their positions.
- Give them skills. Copy the first two cabal skills or make up two crappy, but semi-useful skills/spells and give them to the clan, one for trusted and one for veteran. Clan elders and leaders don't need anything since they should be cabal members. This will give a small but tangible reward to lower ranked characters. It may even aid newbies into getting to 50.
Give the clans a purpose.
Perhaps the new clans should have the old cabal standard do-dad sytem thing. Cabal members could/would ignore the clan battle because generals are worried about wars not skirmishes. But they would be around to push the lower clan members to do something.
Replace the OLD clans.
The old clans crossed cabals. It was why they were created. They served specific purposes. This last RP plot would have be an event that could have caused the formation of a clan. The old Academy clan is another example of why cross-cabal associations need to be possible.
Well, there it is. I had more but the train of thought derailed. Maybe this will get some interesting ideas floating around.