This issue #3336 (PR #4065) removes the "unused" props from the EmptyStateIcon. Perhaps folks were unaware, but the props are in use.
In Cost Management, we provide an icon and color like so.
<EmptyStateIcon icon={OkIcon} color="green" />
My workaround is to wrap the OkIcon, like so:
const MyOkIcon = () => (
<OkIcon color="green"/>
);
...
<EmptyStateIcon icon={MyOkIcon} />
It seems like a simple feature to provide, instead of forcing devs to create custom icons?