We have a blog at https://www.scirra.com/blog which we occasionally post updates to. However generally we're not sure enough of our future plans to announce them - we tend to chop and change to meet user demands and technology shifts (e.g. new platforms being launched) as and when necessary. If we announced anything, it seems there'd be quite a high chance of us postponing it or doing something else instead, so we would rather not announce much at all. Our preferred strategy is to build things then just release them!
We did do a few roadmap blogs a while back - perhaps actually now would be a good time to do another one of those.