In that case, I prefer JSON. Not only because of what @pablo said about having a canonical JSON schema, but also for that 1% of manual edition.
An archetype is not a simple configuration file, as the examples provided show. It is a very nested structure where the use of brackets would be very welcome, instead of having to control the indentation levels by spaces. Just imagine having to add a sibling node here in a plain text editor. It is not about the number of keystrokes, but about the possibilities of introducing errors.
