Apple today (June 2nd 2014) announced the latest version of OS X, which is Yosemite, at its Worldwide Developers Conference (WWDC) in San Francisco, CA with a brand new user interface, iCloud Drive and improved continuity between the iOS devices and Mac.
Apple takes care of privacy to a large level that they donot allow any third party apps to interfere with keyboard access in the past. However, Apple at conference today, showed something that appeared to resemble the popular-gesture based keyboard Swipe running on iOS 8 which is to be released this fall, thoigh iOS8 beta will be available for developers from today onwards.
Third-party keyboards such as SwiftKey Note used for note-taking in a separate app and Flesky allowing app developers to use their keyboard have been launched for iOS, although their integration is limited as mentioned. With this announcement, it is likely that both keyboards will launch for iOS with full integration at some point of time in the near future.
As reported at WWDC, Support for third-party keyboards will be included with iOS 8, expected to be launched for everyone this fall.