I’ll add my tuppence worth from a work/heavy user of iPad Pro (12.9)
drag and drop is fabulous
‘files’ is fantastic, esp as use macs as main computer, all files accesible now on ipad, really good (icloud drive, one drive, drop box all in one place)
‘drag up’ for apps/control centre etc is very good, though will have to learn to stop double clicking on home button (i like this new feature as when reading in bed at night I frequently trigger siri by mistake when double clicking, much to wife’s annoyance)
Only thing I do not like is new process to invoke split view, it requires too many steps compared to previous simple flick from right of screen, and changing app in split view is also slower.