The more time is spend on an early prototype,
the less gamerules have to be "dynamic" to be defined
later.

Its important to define early on what has to be static
content and funtionality, and what should be dynamically
imported.
This defines what a potential editor must include.

Making a game fully dynamic sounds tempting to the developers
selfesteem, but can potentially blow up development time
without adding much value to the product.

Defining functionality very static can prohibit
fixing obvious flaws in the gameplay laster on.

Thats where the prototype must sort out these questions early on.