Certainly unfinished. Unlike Ember, Data hasn't had any releases. There's a reason for this. We don't think it's stable enough to recommend to anyone unwilling to do some hacking.
For sure. To that end, I spend a lot of time reviewing issues and contributing as best I can. From what I've seen, though, I'm not sure if it's even capable of being finished in a way that makes sense.
I'm pretty confident in Yehuda and Tom's ability to figure things out. It's a very difficult problem to solve, as evidenced by the slow pace of progress, but I think it is a solvable one.