Speaking to Siliconera, Feargus Urquhart of Obsidian Entertainment said that they will not be allowing players to respec their characters in "Dungeon Siege III."
The ability to respec your characters has been a staple option of action RPGs because of the inherently tedious nature of games within the genre, with many "Diablo II" players bemoaning the inability to correct simple mistakes in their character builds. As such, "Dungeon Siege III" takes a pretty big departure from the norm.
Urquhart fails to explain the reasoning behind the game's lack of respecs, simply saying that he sees respecs as a necessary function in games like "World of Warcraft" and that he doesn't really see it being "as necessary" in his game. He goes on to tell Siliconera that each of the four character classes only have two skill paths (Anjali can be a spear fighter or a fire mage, for instance), and that mixing and matching skills was ineffective compared to specializing.
This revelation should only succeed in lowering your expectations for any kind of depth that the final game may have to offer.