Since the only way to remove yourself as builder is to get a person in the town to remove it for you I think it would be a GOOD feature if you could remove yourself. On many occasions people are stuck with builder in one town and cant get builder in another town. Now sure people could abuse this to raid but that can be easily solved by either 1 - teleporting builders out of towns when they remove themselves, 2 - just adding a rule saying builders cant raid the town for 24 hrs