Well, I got 7433 from little under a year ago and am trying to figure out how much has changed since then. What brought stuff over the threshold to a version 0.D and what stuff had gotten added in the past year?
That's a huge question.
The 0.D threshold was that there were a set number of specific major bugs and features that needed to be added to be called "0.D", defined a while back. When some of the big ones were finished off, a 'feature freeze' was declared and for a few months only bugfix related changes were added to the project. Then when the biggest bugs were squashed, 0.D was released.
As for features in the last year... I've only been around since October and in that time we've had very big changes to map generation, cities in particular becoming more realistic; NPCs, with tons more added and a lot more background to random generated ones, as well as a lot better AI with features like 'run away' and 'investigate noises' making NPCs behave playably intelligent now although still pretty dumb; better Z-levels with roofs on most buildings that you can climb to and take refuge from; tons of useful features like the ability to drag stuff on the ground, zone management that lets you automatically sort items or do most farming in autopilot mode; waaaay more content and more on the way.
For context, I am a pretty active contributor and after missing a week I needed an update on all the things that had happened in one week to NPC dialogue infrastructure so that I could use those changes in my additions. And the update was long. It's actually getting tough to keep up with how fast stuff is getting added.