More complete would be good. More structured / segmented too. Not a single document. A series that is linked together. We have the technology, let’s use it.
Being cautious of the intent. One way to read that, would be say create a new format to replace the old. Which would of course require breaking code changes. Which would likely break the application, (at least library access) for anyone unable to upgrade. Good idea, but add caution.
Some levels of hard-coding have their place. Here, I think, it should be more of a hard-coded default. I have seen some template files in the source code folders. I do not consider those to be really hard-coded, since they could potentially be modified without touching or rebuilding the code. Assuming they are used as a run time resource, not compiled into the code. Not following the published rules is a separate problem, hard-coded or not.
Screen space is always at a premium. The actually dimensions do not matter though, as long as things are consistent. Double the dimensions (of everything), halve the screen scaling, and you are back where you started. Individual parts that are different are a problem.
I like the schematic connection point lines thicker than the wires. Or some other presentation difference, to make the boundary between part and wires visually distinct. But that is just me.
Constraint for some things is good. Consistency is important. Which exact rule is less important. Artistic license gets tossed out, when it gets in the way of functionality. Which included being to tell at a glance what type of things are being worked on.