Something that has been a tiny bit frustrating for the entire time I've used AN is that once you have enough glyphs that they spill over into the third page, you need to click the arrows to turn the pages. Even though I've done it this way for a while now, it still feels a bit laborious when you're making a spell and need to page back and forth several times.
Proposal is simple, make it so that scrolling your mouse wheel will turn the page. I think this would make the book feel much better to use