I wish I was a good enough dev to write a swift keys replacement. There's AnySoftKeyboard available, and they're doing an amazing job with swipe input which I prefer, but there's only so much one person can do.
Gesture typing is still in early development. The suggestions bar doesn't work yet so it's really hard to use. Nevertheless, looks promising, and it looks like development is starting back up. I'll keep an eye on it.
I have yet to find an open-source keyboard with gesture typing that is anywhere near as usable as Gboard, unfortunately.