We're eager to get it done too! Unfortunately, many of our Developers have been extremely busy with real life lately, and we've hit a couple snags trying to resolve some bugs in our code, so things have been sitting for a bit on the backburner. I'm hoping to get things jumpstarted soon, as summer is coming up, and that means vacations for Developers and fans alike!
Another issue we tend to have is a lack of Developers themselves. Finding people who know C++, know the internal workings of GTA well, will work for free, and aren't already taken by another project makes it extremely difficult to get people that can help out in the project. We are still aiming to make it open source down the road, but it's awaiting finishing 0.5.1 before we do so, so that we can ensure a stable base is made public for all to enjoy.
As for your suggestions about the release dates, they are definitely ones we want to hit, but no promises can be made right now. For Blue too, we have an even tougher time because converting over code is never easy, and sharing both projects makes it difficult to spread out the workload in such a way that keeps both active all the time...so sometimes it's a balancing act. If we can get more help, we can definitely make more progress at an even faster rate. It's just a matter of finding those willing and able.