D2 ist'n party-based RPG, but I wont mind if it would be similar to Drakensang by some degree.
IMHO Drakensang and Witcher are probably two best RPGs from last few years. Im not huge fan of big sandbox games like Oblivion (good by its own merits, but world is too shallow, bad dialogues etc.). Drakensang has some flaws - closing of old map areas, some NPCs are generic (but it can be said about almost all RPGs), level of realism and some quests could be better, some skills could have better and wider implementation. But it was still great game with some strong points - by far the best combat system of all RPGs nowadays (for example combat in Witcher or Gothic 3 was pretty bad), maybe best RPG system (from hardcore point of view), plenty of non-combat skills (its important for me, all Diablo clones allow to kill, explore and solve simple quests, RPGs should offer more), social skills to enhance dialogues, good story, some interesting NPCs and dialogues (it could be better, english translation has its flaws, but some NPCs and situations were great - and again, many RPGs could have better dialogues), little mix of heroic "bright" story and some darker themes (politics, corruption). And no stupid overstuffed and generic huge armors (expensive and mostly useless).
I could enjoy dark game. Fateful game where the world is heading to some terrible conflict or event. Game with troubled hero chased by his own decisions and... his own mistakes. Game when you will try to stop some madness, something out of reach - war between nations, eruption of huge volcano that would kill whole country etc. World driven by aloofness, greed, hate or lack of food - game when you will feel the value of life and value of virtues - to make friend, to cooperate, to be fairly-minded, to have responsibility, to build (not only kill), to know when to fight and when to talk. In dark world it should be hard for a hero to dont let it down in himself and other people.
For example hype about Dragon Age seems like anything but REAL dark game. It seems more like bloody "sandbox" to satisfy needs of mindless teenagers - they want to kill hordes of beasts, they want to have sex, they want to be big heroes (hero is mostly killer, no thinking about purpose of their deeds), they want to have super stuff anybody has (I am the best, i have super weapon +100), they want to see blood and naked girls (symbol of maturity?), they want to be bad guys because its "cool" (at least in games they can act freely and selfishly, no laws, no resposibility, no bonds to friends, no goal, no self-developing, everything is easy at hand etc.). Well its NOT dark world, its in fact childish fairy tale, only in dark setting.
So I agree with Alrik. All RPGs dont need dark setting. And if you want to do dark world, do it right, no virtual copy of fantasy cliché with more blood.
(Sorry for long post)
Note: Heroes should represent something, at least few virtues, right?