You have good reasons not to give a release date.
But may be you could write a post every month or so to show people what you are working on, even if it's work in progress and stuff that may not come in the engine at all. A couple years ago, you used to write really interesting stuff on your blog but it's been a while you did not.
The "development and progress" thread has been pretty quiet too.
Just a quick post, picture or video would make people happier time to time, like your cloud video. Even if it's not perfect, it's really cool to see what you have achieved yet.