As much as I loved games like the BG series the writing/story wasn't even better. BG2 was the typical chosen one story which was also strictly linear after act 2 and completely linear in ToB.
DA:O just as BG2 was a generic chosen one story with a minor twist in the middle and that was it. Heck the main villain was completely void of anything and could have been just as easily a giant lego brick, unlike Irenicus/Melissan for example who had some depth at least.
I could go on and bash any great game but I think I made my point.
I don't think many people would call the BG story very inspired, but at least it was competently put together and didn't degrade the players with absurdly stupid player characters and situations, and the antagonists were at least memorable (though their excellent voice actors helped a lot with that, I must admit; the same dialogue performed poorly wouldn't have been very awesome, but I digress).
Take the opening of D:OS. First thing you come across is some guy who killed himself because he was insane, and the conversation options your characters get is either to condemn him as crazy, or to express how happy they would've been to do the same thing... okay... Then you meet a talking shell who has been unable to reach the sea for who knows how long, despite possessing the ability to throw a huge chest at you from the ocean floor, and sitting right next to the ocean loudly whining about it to anyone who might pass by. Then you are faced with the deep moral conondrum of whether or not to follow some guards to go see the guy you're there to see
... or brutally murder both of them. I found all of these situations extremely childish and stupid. When I very briefly played the beta, before deciding that I'd rather wait for release after reaching the harbor, I assumed these were just there as placeholders to give testers a taste of the system present in the game (which they did well enough)... I was very surprised to see them still there, with the same dialogue, after release.
The rest of the game follows these basic formulas all the way through. All the situations are totally absurd, the characters extremely inane, and the dialogue cringeworthy enough that, honestly, I stopped reading most of it about halfway through the game if I thought I could get away with it.
The main storyline makes BG's story look like a masterpiece by comparison. At least the bhaalspawn didn't stumble face-first into obvious revelation after obvious revelation only to remain totally oblivious as to his or her true nature. The D:OS characters even suffer the indignity of first having it made crystal clear to them by multiple characters that they're some sort of dieties, only to respond to random NPCs they meet in the world, who can clearly see this, with utter confusion. 'What do you mean when you say there's something special about me?', 'Why do I recognize this chest?', 'Why does my brain operate on the level of a 8-months old child?', etc.
Then all the main-storyline's dialogue was all exactly the same. The story was basically told to completion after that video you see where it's explained how that stupid goddess opened the box and started fighting the void dragon (the only thing that still needs explaining is who you are, and that's heavily implied from the start as well with everyone calling you guardians). From then on, all every character in the homestead ever does is repeat the same lines over and over, just said differently. Imp historian repeats the story you already know to you. Time weaver provides the same contentless comments to everything you ask her ('that thing just is because it is because it is'. Yeah, thanks lady, that was real informative.) That shadow demon guy growls at you every time he sees you. The 4 elementals all tell you the exact same thing. Etc. God, and all the bad guy's motivations were so insulting. 'I'm not evil! I don't wanna kill anybody, I just want to destroy everything that exists'. What are you, 13? At least Sarevok and Irenicus had motivations that made sense and weren't just psuedo-nihilism given form (though Irenicus was pretty crazy, and had a high cringe-level worth of edgy
as well, I gotta admit).
Even the ending was insulting to the primary antagonist. You spend forever chasing her, learning about her, and then in the final fight... you kill her just like that and nobody seems to care. Not even her sister is there to lament her death. I still remember Irenicus' last words "It ends like this
?", but I don't think I remember anything the primary antagonist said in D:OS... even her name, come to think of it.
So I feel quite justifed in putting a number like "4/10" on the story/writing aspect of the game, mostly because the storyline was at least somewhat coherent.
The game's saving grace, at least in my eyes, is that the combat is really good (if a bit uninspired), even if it did break down by the end-game. If it was made in the infinity engine, I definitely would not have continued playing it.