You used to be able to set the brightness while reading separately from the system brightness. I used that quite a bit and still miss after many months of beta use.
Being able to tap a theme and switch the settings in one go is nice, if (as is typcial for Apple) you like Apple’s defaults, but it’s a lot more taps to customize. And I wish you could name a theme and have it sync to all devices.
Also I could’ve sworn I saw a setting for showing real page numbers but apparently Apple added that awhile ago and it’s only if the epub supports it.
Off topic from the books UI:
Briefly way back in early iOS 16 betas there were a bunch of extra shortcut actions for books that were really nice. They disappeared and haven’t reappeared even in 16.1 betas.
I still occasionally have issues with syncing, even epubs i bought from the bookstore vs. uploaded into Books. Between iPad and Mac seems reliable, phone is a crap shoot (all devices on latest 16.1 betas)
Pre-Orders, when they ship, will get stuck in this weird mode where it will only show me the preview and the “buy now” button even though I already paid.