I took a lot of notes this morning watching the WWDC Keynote right up until the point they started talking about iPad improvements. At that point I was completely absorbed by the presentation. That's a good sign. I'll be writing/podcasting more about this in the coming days but in the meantime, here are a few thoughts:

It's a Mac ... in a good way. So many of the features were very Mac-like. Spaces for instance is very similar to what we already have in macOS but probably even more useful with a touch interface
Selecting between multiple pre-arranged spaces is a feature I've always wanted without verbalizing.
The redesigned control center is a significant improvement over the iOS 10 three-page version. I still would have preferred to exchange stock apps for better third party alternatives, like switching PCalc for calculator.
Files. Amen. My biggest white whale on iOS is dealing with multiple files. Often I'm required to work with multiple documents and until today this was a huge pain point on iOS. With the Files app and Drag and Drop, my iPad got a lot more useful.
They only demonstrated iCloud in the Files app. Will we get "favorites" from third party cloud document providers like Dropbox?
Does the existence of the Files app indicate they'll make it easier to open and save files to cloud services directly in Apps? That's still pretty clunky.
The new 512GB iPads may make sense if you can locally store massive amounts of cloud data locally on your iPad.
Multiple file selection with gestures? Yes, thank you.
The Dock is another super-useful feature for power users. I need to get hands on this before saying more but that won't be long now.
I have a feeling we are going to be wanting app suggestions in our iPhone docks before long.
They went through the multitasking stuff very quickly. There's a lot there but it looks like a much-needed improvement.
I like the semi-transparency on drag-out multitasking. It really makes the old system feel pedestrian.
I am impressed with the scope of Drag and Drop but want to get my hands on it before saying more.
Interesting how much focus there was on Apple Pencil. It looks like we'll also still be able to use the Apple Pencil to navigate but we'll know soon enough as the beta gets out.
There were significant new improvements to Notes. I didn't expect that.
Scan and Sign looks really clever. I hope it works as well as demonstrated.
The new QuickType keyboard looks pretty useful. How much time have you spent switching between keyboards on your iPad? Related – the 10.5 iPad software keyboard does not quite appear to be the awesome monster that the 12.9 iPad software keyboard is.