If you leave the Chapter 1 tower to have a moat, it is possible for the additional tiles to overwrite important tiles such as the Cave to Izmit.
475811871_04004BFaaJm8eWRai00P is a seed as an example. The Tower tiles have overwritten half of Burland Castle as well as the cave to Izmit making the seed un-finishable.
If you leave the Chapter 1 tower to have a moat, it is possible for the additional tiles to overwrite important tiles such as the Cave to Izmit.
475811871_04004BFaaJm8eWRai00P is a seed as an example. The Tower tiles have overwritten half of Burland Castle as well as the cave to Izmit making the seed un-finishable.