Dom3 progress page lists most changes, from most recent to old. The changes are dated, but unfortunately the page is unavailable for few days. Kristoffer posted that it will be back up in a few days, so I suggest bookmarking it and checking it in a while.
All changes won't make sense, because often they are just names of units being listed. "Oxhead and Horseface", "Hidden in Sand" etc.
If it hasn't been mentioned yet, there are three new giant nations (Hinnom, Ashdod, Gath). Hinnom started off absurdly overpowered, probably still is one, and Ashdod isn't far behind. Besides great mages and units, they have new, great summons. They have unique summons other nations can't even wish for (for EA), and a new non-unique, wish-accessible angel immune to Soul Slay (it has four SC-quality forms), and undead SC chassis in mid-Conjuration (for MA) and other fun stuff. Search for Grigori, Chayot, or just read the HINNOM EATS EVERYTHING! guide. It's a great read.
http://ulm.illwinter.com/dom3/dom3progress.html