Originally planned for release this fall, Divinity: Original Sin has been pushed back to spring. This delay is a result of developer Larian Studios implementing stretch goals which brought in more money to the Kickstarter campaign. The stretch goals included things like a day and night cycle and routines for villagers, and required the team to go back and redo a lot of the game's scripting and add places for people to live.
All of the new changes will certainly make this a better game, and taking a few extra months to make sure everything is polished is never a bad idea. No one ever remembers a slight launch delay, but people will always remember a crappy launch. Take the extra time, and deliver a game that is dripping with awesome sauce.