Hi Nathan,
Handling scope changes progressively is a common pattern on all platforms that support OAuth. In this pattern if the developer adds or removes scopes, the user is prompted to accept the scope changes. If the user does not accept them, then there is a way to query and display messages to users that some functionality is disabled.
There are numerous good examples in the industry for this, the most well documented I have found is Stripe.
This proposal does not include the ability for customers to enable or disable individual scopes. However, we are actively exploring ways for customers to disable features, where each feature represents a collection of scopes and egress permissions. The developer would be in control for defining the feature and the scopes and egress required for that feature. This would allow you to track when a customer enables or disables a feature, along with its associated scopes and egress settings.
Thanks,
James