Surely the best RPG in this decade so far, (Shadowrun and Eschalon 3 are a bit too short)
But hey, so far I considered SWTOR the best RPG since 2010 (No, seriously, give it a try).
But with the big-budget Kickstarter titles on the horizon we'll see how we remember D:OS in 2020.
So, well, D:OS...
There aren't many RPGs with such a complex character system, and most others base on well-established p&p systems, and this amount of interaction with the environment is new (like Ultima7, Shadowlands and Jagged Alliance combined and improved - gods, I'm old.) The interaction between the two player-generated characters is great. Been quite a while since an RPG allowed us to create more than one char, and I can't remember a game that allowed us to roleplay dialogue between our self-made chars.
That said, some mechanics, simply aren't well thought-through. Skills like daggers drawn (twice the AP cost for half the damage? A bargain) or Wind-up toy (yay, I'll gonna summon an insane suicide-bomber right next to me, what could possibly go wrong?) seem to be rushed additions, poisoning and bleeding is underwhelming, and the demon in the homestead makes all but the most overpowered talents obsolete.
The story is average, guess someone played Ultima7 and Baldur's Gate? At least it's original enough to avoid the amnesiac trope and allow the player their own character(s) and still use the character's *past* as story-device. But while Cyseal is a lot of fun, it goes downward in the forest. There are also a lot of dialogue issues later on. Frankly, it might have been better to add a few hours more to cyseal and make a cut there, as it is everything after Cyseal feels a bit like filler-content.
All in all a good game, I have played better ones, but the combination of complex character system, interactive environment and PC-interaction is unique. In a decade that saw the fall of Bioware, it certainly is one of the best RPGs so far, and definitely the best if you take playtime into account.