I've always thought expanding the mist is mainly being done by the artists.
Fixing a lot of the current things and features seems to be more of a programmers job.
The reason you see things in the order they are in now is more than likely based on difficulty of the project. The dev page (while possibly old) shows that there is a programmer with the patcher as their specific job, a programmer where AI is their specific job, and etc. Surely Jordi is probably helping with all of it, but that's not really the point. The point is that they are probably doing all of those things at the same time to some extent (except maybe the last 1 or 2), we will just see improvement come in the order shown. This also gives the new programmer more time to learn the specifics of Xsyon's coding style.
Those are my thoughts. However, I consider the game going live when pre-orders closed.