Yeah, it's quite silly. I agree that it should be put on pause until a new one is decided on, although to reflect the problems his death brought to the project maybe it should lose 25% of it's progress or something. Just disappearing is very strange. We aren't the ancient Emperors that actually demanded that a new main palace be constructed for them individually as they ascend to the throne.
Summoning is complete!
and why the death of master of arms would remove all his work done till that? was he casting a spell to create new castle?

Summoning is complete!