Claiming shouldn't be restricted to square plots of land. If you could create irregular shaped claims it would open up the possibility of saving large amounts of LP by claiming only the area you need; like on a peninsula. Instead of claiming the water that ANYBODY can go on, just claim the land part and save 70% of the lp.
It should work like the old claim function, control L, but with some slight changes. After you build your claim stake, you right click it and the control L styled menu pops up. To select the land you want to claim, right click and drag(so you can move the view and your character with the other two buttons). Click claim. To avoid people being boxed in you can't make a claim that has a gap in the middle, and so you don't claim 8 different plots of land you must start dragging your claim from an already existing claimed tile that you own.