One of our biggest frustrations with iOS devices has been the less-than-stellar stock keyboard. iOS 8 fixes that with Quicktype, a predictive, content-sensitive keyboard with multiple layouts that learns the phrases you use most and fills them in. It's about ducking time.
Update: Thanks to Extensions, iOS 8 also supports third-party keyboard apps (like Swype) now. Hooray!
At today's WWDC, Quicktype was revealed as a learns-what-you-say keyboard. So if you happen to say "turn down for what?" a lot in your texts or emails, it'll recognize when you start typing "turn down..." and offer to finish your phrase for you. It's also context-aware, offering different auto-fill suggestions based on who you're talking to (so you don't accidentally tell your boss to "eat shit and die"). All the learning happens on your device, not in the cloud, for your privacy.
This isn't new tech—Swiftkey users on Android devices will recognize this predictive typing. And Swiftkey is already sooort of available on iOS; it's just buried in a note-taking app, far from the texts and emails where you want a good keyboard. Finally, finally, Apple's giving us the alternate key layouts, expanded character sets, and predictive typing the iPhone and iPad have been so painfully lacking.