I think the solution is to leverage views so that you are working on, and therefore viewing, a small enough subset of your realm that having it all open at once is not an issue.
Well, if we could create a lot more views, I might accept this as a solution. But we are currently limited to seven views.
When views were first released, I was excited and started creating views for different regions of my campaign world. I quickly used up the seven available views.
I ended up deleting the views and stopped using them until recently. I now use them to create game-session views. I usually only have a single custom view for the current game session.
When creating content, however, I tend to jump around and will have multiple tabs open and I try to apply search filters where appropriate. But I still frequently find myself needing to browse through the hierarchy in the side bar.
I would love to have persistent collapse and expand states. But I've learned that this might not be practical.
I would still like to set a default collapse state. Personally, I would prefer to dig in rather than have everything open. I'm guessing most people would rather have everything expanded and scroll up and down. A preference option would be nice.
But the most useful would be filter-as-you-type functionality. So I can start typing in the search bar and as I type "gob" I'll see articles on goblins, goblets, and once I get to "gobli" I'll just see the goblins article. That said, I'm guessing that this can be resource intensive. Evernote offers this functionality and frequently freezes for a short amount of time while typing your search. That can be frustrating when you have a long word or phrase to search for and you have to keep waiting for the search to catch up to your typing.
If the search-as-you-type only included the topic/article titles rather than searching the entire content, that might be a good functionality vs. performance compromise.
