I don't want to give any estimates as they would just be broken, lead to user disappointment and put unnecessary pressure on us.

But I can tell you that from the bits that we have left, none of them require any internal architectural changes and it's mostly just implementing missing bits and pieces.

We have two major improvements that are left to be implemented (I'm in the middle of the first one) and the rest are minor. For example, document zoom is trivial to implement (practically, it involves putting some UI controls and some small bits of code to tie loose ends).

I'll be very open about the development process and try to keep everyone informed as much as possible. My advice would be to follow @Monodraw, our blog and/or myself (@milend).