As I find DS I and II super archaic I will not consider them in my review. Dungeon Siege III is a mediocre game in every possible way. Plot is mediocre, gameplay is mediocre, RPG elements are extremely simplistic, game is 100% linear. At the same time, it is fun to play... kind of. Sometimes it's boring, sometimes not. General art style is enjoyable and unique I would say - only in this game you can see anime-styled ladies shoot Hindu gods with muskets. Somewhat enjoyable, somewhat not. DLC - more like Dull Lame Content.
The most relaxing and funny city builder I have ever played. Hilarious mission objectives, supreme soundtrack that never gets boring, many possibilities of making money, lots of building to choose from, AI of citizens can handle large cities. Only battles with rebels seem too random for me - sometimes you can loose many soldiers only because rebels move in huge stacks and soldiers don't. Generally speaking - awesome game!
As I said - game is fun until you realize every game will look absolutely the same. It takes 15 minutes to get like 80% of votes and than... nothing to do. Plus DLCs are absolutely useless. I need also to mention you pretty much need to be 150%-socialist. Otherwise - you will fail immediately.