I believe it would greatly improve the user experience if we can add a "folder-like" grouping function to content types (single type and collection type), so that if you have a lot of content types (for example if you have like 50 webpages, you will have like 50 single types), it really makes a lot more sense to have groups. For now users can only mitigate this by using some naming conventions, but I doubt if this is an elegant solution.