I'm posting this despite the fact that my group has actively abused the fuck out of this, but pclaims are way too easy to set up and then way too hard to break once set up (no one is going to break the thing peace just to siege a grief 10x10 pclaim for 24 hours). I currently have 2 alts with 40 int who maintain a combined 30 pclaims with ease. It's actually really stupid.
Problems
Multiple small pclaims can be maintained by a single alt chain studying shit curios.
Once set up, pclaims require the thing peace to be broken to be removed by other people.
Pclaims can be very close to a vclaim (5 tiles) while only taking 8 hours to dry meaning a simple siege claim can be set up during a villages down time. The village would then have to break their own thingpeace to remove this siege claim. This is especially problematic if villages don't extend their v claim pretty far out from their walls.
I think pclaims shouldn't be protected by the thingpeace. I think they should be able to be declaimed instantly with revoke the privilege rather than the vclaim needing to wait until the vclaim is 90% as old as the vclaim (this shit literally takes weeks even if you catch a troll pclaim near you fairly quickly) and I think pclaims should have the same building restrictions as vclaims (can only be built/extended 100 tiles from v claims)