This game's boss battles had a Ninja Gaiden feel to them, Ninja Gaiden is the only game I've ever returned to Gamestop because I abhored it. The one shot boss hits that are more random than avoided through skill get tiresome. That's my major complaint and why I gave up after halfway through the game. If they did a sequel I would not play it or purchase it.
I did enjoy the game's story and the combat between boss battles which was challenging but not frustrating, their was a good balance but when it came to the boss battles it was not fun, it was just frustrating when it seemed they were based more on luck than anything else. The Davae for instance has one attack that you can avoid if you aren't standing still which is cool, you just run around and stop intermittently to fire but if you end up stopping at the same time as the Daeva fires her attack you are dead before you can hit your block or roll out of the way. 2k hp plus in one second is not a attack it's a character wipe. The boss battles broke this game for me, if I can't beat the game on normal with out having to go through the same boss battle more than 6 times then I count it as fail. I don't want to waste that much time into something that basically is more luck than skill.
I talked to some people who teach programming and game design and they agree that the game was designed with a niche gamer in mind and that gamer typically goes for the aabbcccddeeefff button mashing games as opposed to RPG's which Dungeon Siege has always been, the combat just seems really out of place. The character development is a joke and the equipment drops are laughable. Your only stat you see a significant improvement in are attack/will/stamina those three will define any character the rest our incidental.
Over all if I were to grade this game the following....
Character Development: C
Combat: F (Combat is fun until you get to certain battles where you get one shot killed, that is automatic fail.)
Graphics: A+
Storyline: B+
RPG Element: D
Where it tried to capture some strong RPG elements from games like Dragon Age and Mass Effect, it failed to this by implementing frustrating boss battles and stat and equipment systems that failed miserably. That left the most important element in a dungeon crawl RPG, loot, to be unimportant to the point where I bypassed chests after awhile because I knew nothing was going to make a dramatic difference in my character. You can literally use your starter equipment 80% of the way through the game and not notice a huge difference.
Overall the game gets a C- in my book. Which is sad it could have been so much more if they had tweaked the boss battles and changed the loot system to be something fun and fundamental rather than incidental.