Like iOS, Windows Phone users can't change the default keyboard for the system, so any added text-input options have to come directly from Microsoft. The stock keyboard works very well, but Windows Phone doesn't yet have universal dictation or swipe input, but it looks like both may be coming with WP 8.1. Universal dictation is expected to be part of the Cortana voice command expansion, and new rumors have been pointing to a gesture keyboard in the works as well.
The video below isn't the best quality, but it does show the new keyboard in an early version of WP 8.1 on a Nokia Lumia 920. The gesture input is what you would expect, but there do seem to be a couple added bonuses. For example, if you swipe the word "happy" there will be a recommendation for a smiley emoticon. That seems pretty cool, although if you've already swiped "happy", it seems a bit silly to change that to an emoticon. But, maybe we're not the right demographic for that use since we aren't teenage girls.
The latest info says that the Windows Phone 8.1 developer preview should be released in April with the full update hitting consumers over the summer.