Aside from Voices which will take a while, I'd say...
Music (few more tracks missing)
HTL and fixed versions of some (and by "some", I mean, quite a few of them) models. The major ones have been worked on and are being worked on currently so that's good news.
Cutscenes (though these will most likely be optional - depending on how fast the other stuff goes... it would really be good if we could get someone to do them proper though, it would... complete the picture)
Ace is finishing up the Skyboxes I think and we're almost done with the complete rebuild of the missions (that was one behemoth job both for Ace and myself, kv pitched in a lot as well), just a few left, waiting for me to get my computer operational again. (maybe I should put a PayPal "donate for BD's new computer so BWO will be released faster" fund hah).
That's more or less it. The rest are kinks and assembly. There is really no time estimate. It all depends on when it's all finished. If everyone dropped their lives and commited to BWO solely (everyone we need), we could be done in three weeks. But since that's not realistic, I think it'll be a while. People have lives and other things to do.