More or less, yes I think so. I believe there are now new feature requests that could apply to the existing sidebar, for example a way to view all objects in the sidebar (like you can in Notion, for example). But since we already have a sidebar, the core feature request here seems addressed. That said, read on…
I think this would ideally be a separate feature request, and would hopefully be well described so as to reference the current/existing features/functionality that we now have with the sidebar as-implemented, and then suggesting either specific changes to it, or perhaps suggesting an entirely alternate (additional?) type of sidebar navigation helper. In other words I think further discussion of such customization needs to keep in mind that the current implementation of the sidebar would very likely not be extendible to “just a page that can be fully customized” as some previously (more or less) suggested. So either there needs to be a concept of customization that fits into the existing model (collapsible sections, basic parentage/hierarchy), or the suggestion needs to take into account that it is suggesting some entirely additional type of UI feature.
With all that in mind, I think perhaps someone would ideally take on the job of describing a new feature request for customization, and then the discussion relating to customization could be merged into that new request (unless there is an existing reply above that seems like a good candidate to anchor a whole new topic on a customizable sidebar feature).
I would also suggest that any new feature request around this needs to specifically address why the existing Favorites functionality is not customizable enough for their needs. I.e. what exactly they want to be able to do that is not possible with the current options.