I was also wondering about whether or not the new Search can be brought up in-app through touch gestures. Because there's no Calculator app, I use search constantly to do math on the iPad, and I've always wanted to be able to just pull it up right over the app I'm using.
Also, besides not implementing the App Library and home screen widgets, the HUGE part of iPadOS 14 that is just a tremendous disappointment to me is that Apple completely neglected to solve the absolutely mind-bogglingly horrible process of picking apps for split-screen multitasking. I'm holding out hope that they are waiting to introduce the App Library because they're somehow going to use it as the new app picker for multitasking!