I disagree. If the area is too big for your blacksmith, then you could consider building it in the left part of the baseplate and then just have a regular wall in the right part of it. Or perhaps a small fenced area with pigs or chickens or whatever. Use your imagination.
Moving the beginning of the wall on each baseplate inwards would allow a build to move outwards. This will become handy when building a corner. And again, if the space between the wall's starting point on the baseplate and the edge of the baseplate is deemed neccesary for a build. Then use your imagination and build outwards.
Are we going to have a rule on the design of the catwalk (if any)?
I think the only rules should be:
1. The wall has to be 3 studs wide.
2. The wall's "ends" are situated 4 studs from the edge of the baseplate.
3. The wall has a 1x2 brick with technic pin hole at 1st and 6th space counting from the baseplate.
4. When cornering the same 4 studs from the edge rule applies.
5. The wall is to be built primarily in light grey (adding other colours in a controlled manner is allowed)
See the below pics for clarification (yes I know I've used yellow. Strangely it's the only colour at my workspace right now)
The Wall height and 1x2 bricks with technic pin hole:(you are allowed to build higher than this)
Straight wall section:
Cornering:
How'd ya like them apples?