Apple has released an update of iMovie for iOS devices that can edit 4K video, which the new iPhone 6s and 6s Plus can record. However, iMovie for OS X El Capitan hasn't received a similar upgrade. Also, what's (not) up with all of Apple's iWork apps?
Sure, it's nice to be able to edit 4K videos on the iPhone and iPad. Still, I suspect more folks do their video editing on the Mac. Perhaps Apple hopes those who wish to edit 4K video in Mac OS X will spring for the US$299.99 Final Cut Pro X app; however, feature parity between the iOS and OS X movies of iMovie would be extremely useful.
As for the iWork apps (Pages, Keynote, and Numbers), they need an upgrade. As Dan Moren pointed out in a Macworld editorial, none of the iOS versions have been upgraded to take advantage of the iPad productivity features (such as Split View and Slideover) in iOS 9. Neither have their OS X counterparts been revved to take advantage of any El Capitan features.
Moren worries that the iWork apps could be headed down the same path as Aperture, iWeb and other Apple-developed apps that have gone the way of the dodo bird. I think (hope!) he's wrong, but some updating from Apple would be reassuring.
In fact, I'd love to see Apple take Pages, Numbers and Keynote even more seriously. Release Windows versions of them and make the iWork tools true Office competitors.