Try to imagine Obsidian's role-playing dialog system embedded into the console port of Diablo III. In a nutshell, that's Dungeon Siege 3.
You'll notice that the majority of negative reviews on here can only be summed-up the way Machinima's Inside Gaming Daily recently described most haters' opinions. It goes something like, "I hate this pizza because it isn't a taco." Granted, it isn't wise to change a franchise as much as Obsidian did here. Many fans of DS1 and DS2 appear incapable of liking this game, and it seems a lot of them feel tricked out of their cash. I'll mention their gripes here, however, to give a fair review, I don't want to just look at what DS3 *isn't*. I want to review it based on its own merit. To be up front, I actually hated DS3 at first, but when I was looking for a co-op to play with my non-gamer wife, I took a second look at Dungeon Siege 3. I found I had completely changed my perception of this game, because I changed my perception of its design choices, and it actually became one of my favorites of all time.
Dungeon Siege III is a gamepad-friendly isometric action RPG with local and online co-op. While much more casual than its predecessors, there's still plenty of quests, hacking, slashing, shooting, magic, looting, upgrades, lore, and dialog - and when multiple players (online or off) are in a story conversation together, players can vote for their preferred responses to NPCs, albeit Player 1 has the final say.
There are four characters to choose from, and each delivers a different fighting style (melee, ranger, sniper, magician). Each character also has two "stances" to vary up their attack strengh, range, and/or speed. Not to mention, the back story will also change, according to which hero you've selected.
Gone is the tactical pause. Gone is the squad management. Gone are the skill points you earn, specific to your fighting style. Gone are the multiple skill trees for each character. Each weapon and piece of armor you find can only be equipped by a specific character. Obsidian has "streamlined" this game, effectively consolizing it. This is the heart of Dungeon Siege 2 fans' complaints, besides multiplayer camera controls and multiplayer inventory management. You now will be only upgrading a single skill tree for your character, which means close vs ranged combat will not award skill toward that specific stance. Instead of holding down on right-click to attack, you'll button-mash, and each press will be one swing/shot. Also annoying to some, even when you gain NPC followers, you will not be in charge of their tactics, nor their upgrades.
This game was developed by the same people who made South Park: The Stick of Truth, Fallout: New Vegas, Knights of the Old Republic 2, Neverwinter Nights 2, and Alpha Protocol. I loved all of those games. My point, they KNOW role-playing. In my opinion, the story here is great. If you don't have nostalgia stars in your eyes, it's easy to see that the voice acting here is by far superior to its predecessors. Although the story is drastically shorter, it's certainly more focused.
All in all, I can tell you this: if you have a friend or loved one you want to play an immersive, open-world action RPG with while sitting on the couch together, this is the game. You'll find a rich story, a simple skill tree, upgrades, dialog choices, and tons of loot. It's one of the best (and few) couch co-ops that delivers a true RPG experience. Plus, gamers of all experience levels can enjoy it together.
I come from a Fallout 3 background, but my wife is really only good at Bejewelled and racing games. While I was able to try to craftfully master my character's moves, she was able to button-mash with a rifle-wielding hottie from a distance, and we made an excellent team! We were able to hack/slash/loot our way all the way through the campaign +DLC together and we both had a blast. If you've ever played/enjoyed Diablo 3 or Daggerdale on the couch with friends and/or family, and you like the idea of breaking up the action with cutscenes and dialog choices once in a while, I'm telling you, this really is an awesome game.
If you're looking for the next 100-hour tactical RPG in the Dungeon Siege universe, buyer beware.