I had this idea from the beginning of the realms, we claimed from from the other end to the other end of the world in just few days which is ridicolously easy and I didn't post this idea since I would shoot in my leg if the devs implement something along these lines in the game since our claim was just a straight claim from a end of the world to the other end, but now when we lost our realm it doesn't matter.
Make it so that if a realm straight claims, it is possible to cutoff it by destroying a point of the claim that would leave a gap between the main claim that is connected to the coronation claim and to the other side that isn't, the rest of the claim that is not connected to the main coronation's claim would get destroyed. This would keep the easiness to build, but you would you would take a great risk if you decide to straight claim far distances.
here's a small diagram I made
http://i.imgur.com/gzHs5hV.png
Every rectangle is a realm claim, the biggest one is the main claim, if they wouldn't want to get destroyed so easily they would have to make their claim to the place something like this:
http://i.imgur.com/ocnb97N.png
there would be no cutoff points, it would promote realm claims like this.