It looks like iOS users who are looking for an alternative to the stock keyboard can look forward to Fleksy SDK. Fleksy for iOS looks like a way to customize the look of the iPhone's keyboard to complement iOS 7's many hues as well as the iPhone 5c's colourful polycarbonate shells. Fleksy SDK seems geared to developers who want to spice up their apps.
There doesn't seem to be any advanced predictive text or Swype-like functionality which isn't surprising, it is unlikely that Apple will open this aspect of the OS to a third party developer. From what we see from the above leaked photo and from Fleksy's own website is that this is a way to get larger keys and a neat way to skin your keyboard, if you're into that sort of thing.
Source: Fleksy SDK