Don't know why I waited so long to play this one!
All of the achievements are possible, but can be a lot of work. My personal un-favorite is the "get all treasures/items/weapons/whatever in the game" chievo, as it's pretty easy to miss one thing somewhere. LO is relatively forgiving in this area, as you can buy at auction anything that you missed in areas that are no longer accessible. This is great! Unfortunately, I missed something in an area that I could return to, so I didn't get that last achievement. 100+ hours already in, I didn't want to spend more times searching.
The game's 'dreams' are a definite plus. Very well written, they give you a glimpse of backstory that you would not have otherwise. They are skip-able, but don't do it.
All in all, it's a great gaming experience for the RPGer on the 360.