I have just finished the game as Katarina on normal. It took me 3 days (patches....) to finish. I already knew of the multiplayer issues so I tried it once, laughed, and then left to play my single player. First off, this is by no means worthy of the name Dungeon Siege 3. I played DS2 quite a bit and the controls were a bit funky in that too so I wasn't completely bothered. However if the top brass instead called it "Dungeon Siege:10th Legion" they would not have pissed off 80% of the PC gamers. That one change will justify all the content of the game. For example: WoW not Warcraft 4. Assassasin's creed:Brotherhood not AC3, Sims:Medieval not Sims 4. You paid for the Dungeon Siege name, and you can use it and its lore. You will still draw interest from people who played the other DS games but if its not a sequel, don't try to call it one.
That aside, there are a lot of additions and adjustments to be made to the PC version. First, is key bindings. Any game that uses more than 5 buttons needs key bindings. Absolutely no excuses for this one. Also, if you are going to port something over to a m/kb, let me use my mouse as it should be used and my keyboard as it should too. Katarina has some curses she and I try to highlight the target and use the ability, but oh wait she is not facing that way and the curse is used on myself and completely wasted. Then, there is a wounded creature in the background who is pelting me with arrows, so I click him. Oh wait, my character isn't facing him, she is facing the barrel on the side of the room and I waste my shots to release some gold. If you are going to give us AoE spells that aren't always player centric and 360*, we need a way to place them exactly where we mean to place them. Katarina is a bit of a glass cannon (as ranged characters should be) and survival is highly dependent on controlling mobs and getting good positioning. Power is nothing without control.
Another adjustment needed is the quest tracking. There are times where I am in an area and have a main quest and a side quest to do. There is no good way to see both, so often times I complete one and then rerun through the entire area again to do the other. This completely wastes my time and is keeping me from all the fun parts of the game.
Lastly, if you are going to give me a companion that is supposed to be as complex as my own character, give me some semblance of control. Since I was Katarina I wanted a melee character. I would have loved to use Anjali in human form or Reinhart in electric form (?) but they would often switch stances and sometimes I felt I would be better off with no one. I used Lucas cause he was full time melee and once I got him, I never used the others, at all. The only way to justify companions is control, or pure simplicity.
Overall, as a single player game, its an alright game. Linearity in the plot reduces its replayability. Also, its not a terribly long game and the lack of 'nightmare' and 'hell' again hurts replayability.
It dared to call itself Dungeon Siege 3. It isnt. Given another name, the rose would have smelled very sweet.