I agree as well. It would indeed be great if the old docs can continue to be supported. I think that its compact tree-like interface helps give a nicer overview of all pages/topics/subsections in a single page, enabling easier navigation with a fewer clicks.
Apart from the interface, we do particularly miss the ability to link to subsections and release notes in the new docs. This can be done with ease in the old docs and it has been of great significance in our development process and in knowledge sharing.
The new docs also seem to be missing the Glossary reference. I think the links to glossary references in the old docs are very useful, especially to newer users.
Hoping you can consider this request, it will definitely help us. Thanks!