Is it possible to reinstate our links to favorite posts in the semi-permanent sidebar? Or did we lose that feature with the redesign?
The links you refer to are the "featured" items. Those are the ones with the tag featured.
When you add such tag, the Community user removes it afer 30 days so that it really is something temporal and not forever. That's why it keeps disappearing and we keep adding it to a set of questions, trying to keep some rotation.
I added this tag to a couple of them and now they show in the yellow box in the right side of the page. So the redesign is not affecting this feature and it keeps working as always.
You can read all the details about this in What criteria is used to select the links that appear in the “Hot Meta Posts” block? and suggest some posts by flagging them here in Meta or reaching us in the chat.