Rather than editing settings directly through a text editor (which is really the poor-dev's-solution to this problem even if it involves creating a json parser), make settings available through a friendly UI.
[ ] Every setting property must have a localized description
[ ] It should be possible to group related settings together
[ ] Design an algorithm which automatically generates UI controls based on the current settings schema
[ ] Every type of setting value must have a localized hint about what values are allowed or have a specific type of UI control associated with it, which allows legal values only (e.g. color control for color values)
[ ] Live preview of setting updates, with appropriate 'apply', 'cancel' and 'ok' buttons
Rather than editing settings directly through a text editor (which is really the poor-dev's-solution to this problem even if it involves creating a json parser), make settings available through a friendly UI.