Monday's WWDC 2015 keynote talk was a jam-packed day of announcements that included iOS 9, OS X El Capitan, watchOS 2, Apple Music, the News app and updates to Apple Pay, so much so that Tim Cook had to immediately cut to the chase and skip his opening round of business updates (“Everything is going fine”, he joked).
There just wasn't enough time to talk about every little enhancement and nice-to-have so Apple execs focused on big ones that make for great headlines while relegating a bunch of platform updates, that mostly matter to developers anyway, to a single slide.
My colleague Cody already compiled an interesting list of nearly three-dozen features in iOS 9 that Apple didn't talk about during the keynote. If you've found his post compelling, you may be interested in my list of technological improvements in OS X El Capitan that Apple didn't show on stage.