Probably a niche request, but I was thinking it might be nice to be able to have widget cards that display one of two widgets based on some sort of criteria.

The most useful example I can think of (though there are probably others): if no books are marked as currently reading, show the "Your Next Read" widget, otherwise (if there IS a book currently reading) show the "Currently Reading" widget. In that example you would be able to have a more concise layout instead of having both widgets taking up a space.

Someone who wants the "Your Next Read" widget always visible to help find their Next-Up could keep both in separate spots if they wanted, but if you only cared to see Your Next Read when you're in between books, you could opt for the conditional format.

There could also be a rotating option where you choose two widgets and on each load/refresh it rotates which widget is displayed (like "Reading Goals" and "Stats - Last 365 Days", for example). If you preferred a compact dashboard, this would allow you to keep the same information but compress a little bit.