I'm looking forward to the whole activating the world idea, as well as the combat overhaul, if I had to pick. The release I'm guessing will be at LEAST several months. It largely depends on how much he decides to add. He could make this even more far reaching than it already is, and it may take over a year.
If someone wants a list of what has been added thus far in the update, and is in the process of being added (to my knowledge and memory):
Remade combat (inculding non lethal combat)
More control over character in terms of movement
Complete reworking of stealth and detection
Sight revamped
Hearing actually implemented
Beginning of activating the world
Armies and such in play, towns and cities being seiged, political succession, people actually needing to eat and drink, as well as groups harassing towns/hamlets
Personality rewrite (people and creatures will have more dynamic reactions in terms of how they deal with stressful situations and such based on what they've been through, etc)
Goblins, kobolds, dwarves, elves, and demons having their own sites
Criminal lairs
No more immediate enemy recognition (no all seeing hivemind)
Reworked entity claims
Adding an actual use to the tracking skill, you can track things, things can track you. Various forms including of tracking including sensing through blood.
More quest variety
Multi-Tile trees