I love the concept but it crashes all the time

I have an iPhone 4S and at the beginning it was working as a charm. Its really fast. Two days ago it started to take a long time to open. Yesterday I had to uninstall it because it crashed all the time. Please fix it, Ill totally continue to use it.
Update : I changed to a 5s and was working well, however it started to crash again. When I want to type something, all the keyboard area stays gray. I cant type anything so I have to go to settings to uninstall it so I can use the built-in keyboard.

GACI about Swype, v1.6.2