@Bolingbroke and Martin Milner:there is at least one add-on for the new castles. It only adds one length of wall, BUT, if you look closely at the side opposite the double-doors: there is a second storey there, which means you CAN build upwards, doesn't it?
Martin, I agree with you, this non-too square shape is a great step towards reality.
Cheers.
Arnaud