UI for mail type creation is not consistent with UI for mail type update

When creating a new mail type from administration page (MailArchive.Admin), sheet used is MailArchiveCode.TypesSettingsCreation.
This sheet contains complex form for entering matching patterns (with checkboxes for fields, possibility to add/remove patterns, ...).

When viewing/updating a mail type, sheet used is then MailArchiveCode.TypesSettingsSheet. This sheet is a very simple display of all fields of object MailArchiveCode.TypesSettingsClass. It does not propose at all the same level of ergonomy to add/remove patterns, etc.

The same sheet should be used for creation/update, in order to give a more coherent view to end-users.