Many changes seen to come with the game. Just from the images it looks like a mixture of Civilization and Age of Wonders. From the Overview description provided, it seems like races won't be as limited, since it mentioned that you pick a "starting race" and that the player won't be limited to "fantasy clichés like All Goblins are Evil".
The leader, which at first was a Hero in AoW1 and then a Wizard in AoW2 will now be more customizable and with specializations typically found in RPG games, which is shown in the trailer.
It is still very early, but I am happy that I game I've been playing for over 10 years on and off will come back in a new edition.
Official website: http://www.ageofwonders.com/aow3live/