Speaking of iPad screens, I've always hated how — unless you had a physical keyboard connected to it — iOS's keyboard eats up a third of the screen. There's a fix of sorts for that now in the form of an iPhone-sized floating keyboard you can toggle from the main one. Typing while holding an iPad mini in both hands is one thing; trying to do the same with an Air or a Pro often felt ridiculous before this tiny new keyboard made it easier to peck one a letter at a time or swipe out a message with the new QuickPath keyboard.
Apple also made some changes to how you might edit and copy/paste your text. My days often involve lots of running around with an iPad, for taking down notes and whipping up the occasional script. It sounds pretty minor, but you can now just drag the iPadOS text cursor around the screen and drop it right where you need it. (It's not quite as satisfying as the 3D Touch equivalent, but it's handy all the same.)
Selecting text is pretty easy, too: Just double-tap a word, and drag across the screen to highlight the appropriate bits. I say "pretty easy" because it still requires a bit of trial and error to pick out exactly what you needed, but it still feels much more precise than it used to. Since you're probably highlighting text to do something with it, iPadOS uses some new gestures for copying (pinch three fingers together on the screen) and pasting (the reverse). If that sounds a little awkward, well, you're right — it feels more natural on these big screens than on iPhones, but I'd still much rather long-press on the right spot and just tap "Paste".
There are, as always, other methods of interacting with iPads beyond fingers on glass. Apple has been pushing its Pencil for years, and the company claims that software improvements have brought the latency on both versions of the stylus down to 9ms. If you're anything like me — that is, a poor doodler and infrequent note-taker — the difference won't feel drastic. Still, it's there, and it does make drawing feel slightly smoother and more natural. The palette of tools that pops up when you start using the Pencil has been also redesigned, and you can flick it around the screen so it doesn't obscure whatever you were doing in the first place.
I should point out that I haven't had a chance to thoroughly test Sidecar, the feature that lets you connect an iPad to a Mac for use as a secondary display or a drawing tablet with the Apple Pencil. As of the day we're publishing this review, macOS Catalina (and therefore Sidecar itself) is only available in beta form, so I'll revisit this part of the review once all the final software is available.
Oh, and if you really wanted to, you can finally use a mouse with iPadOS. I wouldn't recommend it, though. You have to dig into your tablet's accessibility settings to enable AssistiveTouch, plug in the mouse or connect it via Bluetooth, make sure your mouse sensitivity is set to a manageable level, define what (if anything) you want your mouse's other buttons to do, and then finally get down to business. The process is slightly cumbersome, and there's no question that iPadOS — improved as it is — isn't meant to be used with a mouse yet. The thing you have to keep in mind that this is an accessibility feature, not something meant to redefine how most people use their tablets. It works, but it's not going to magically turn your iPad into a Surface Pro.