For French people, there are an interview and an article about DomIII in the cybertratège magazine. There are some screenshots.
http://www.cyberstratege.com/
For the infos, they talk about
:
*subterrean races and castle
*the system of era
*the random map generator
*the awakening system (the pretendant can be in sleep at the start of the game)
*better IA (more castle construction)
*lesser powerful drain life
*lesser "micro-gestion"
(sorry for the bad english)
edit for Dominionsfan: in the interview, they clearly say no diplomatie for the moment