I'd like to suggest that when hit for land the acres you lose come equally from the land you have currently built and the land you have in progress.
Example i have 1000 acres built & 1000 acres building
I am hit for for 1500 acres i end with
250 acres built & 250 acres building.
(or say 1500 built 500 building down to 500 u end with 375 built 125 building)
Reason: Its very strange to be chained from 2000 acres and end with 40 build acres and 650+ incoming acres, kinda get screwed when you lose all your farms/guilds till your land comes in in 12 hours.