This article will help you with this. We have removed the legacy layouts to maximize the benefits of the overall blog improvements. Rest assured, these changes will not affect the designs and you can still achieve them with the help of these options. Let us know your layout design and we would be happy to help you out.
I can understand but you can also achieve the full-size archive layout with these options as well. Refer to this screencast, please.
However, if you would still like to revert to the legacy layouts, you can do so by adding the following filter to the functions.php file of the child theme: