It isn't just Gaider who writes everything. He has a whole team of awesomness who work beside him tirelessly during production.
Also, I reckon that the insane amount of pressure and time constraints were to blame for the random, "SURPRISE IM EVIL" stuff in DA2 and the time jumps that didn't have any realism to them (oh, it's been 3 years and nothing looks different? Cool.) Usually their villains have way more backstory or empathy to them (Loghain was totes on purpose, as was Bhelen) unlike a cruddy fighter game come soap opera (sorry, Tekken, but your story got crap when you made Nina become a mother.)
I know Gaider is not the only writer, but he is lead writer and I assume that means he plays a large part in writing the main story and that he approves what others have come up with.
I honestly don't give a damn about their time constraints. That's still on Bioware's end, not mine. I am not going to feel sorry for them or cut them some slack because the company felt the need to rush the game for as much money and as little time and work as possible. And even if time was very limited, the fact that all they could come up with was "because crazy" does not suggest a lot of creativity. I would think that writers who are being paid for their work can come up with a little more diversity. They were on the right track for a while. Both Meredith and Orsino seemed to have point. But then one became insane because red lyrium and the other one because blood magic. What a surprise. Even the Arishok, who received the most development as an antagonist, needed a fit of crazy I-am-so-homesick to break his Qun character and have him wreak havoc.
In addition, I have never seen anyone at Bioware, least of all Mr. Gaider, admit that DA2's story was... less than flawless. Whenever someone of the company comes out and plays their little act that they acknowledge DA2's problems, they always, ALWAYS mention the same: recycled environments and enemy waves in combat. They add in an "etc" or a "yadda yadda" to suggest that's not all, but nonetheless these two are the only things they will explicitly mention. Annoying as those were, they were not what ruined DA2. If the story had been good, I would have suffered through the same endless cave with enemies dropping on my head over and over again. The story was not good. It was bad even. And not because it was "different than expected after DAO", "too much change" or because it would not let me "play the hero and save the day everytime", or - my favorite - because I am "too stupid to understand it".
Instead of acknowledging that things could have been handled, Gaider chooses to actually defend it. No, DA2's cliffhanger did offer closure. It might not have been enough for SOME people, but that did not mean that they did not offer closure. Well, sorry Mr. Gaider, but having Hawke mysteriously disappear AND dragging the Warden from the previous game, who had received proper closure beforehand, along with him is the very opposite of closure. It's a cheap trick to get people to buy the next game even after DA2's drop in quality.
Tallis (yes, I was foolish enough to even buy the DLC for this game. What can I say, my love for DA2's companions blinded me for a long time) was the first companion in the DA series I could not stand because she was poorly written and felt like fifteen year-old self-insert (oh, I am funny, I am bad-ass so I murder a bunch of assassins and wink at one of them before slitting their throat, but wait! I most be deep as well, so let me be sad over this guard I just killed), but will that be acknowledged? Nooo, I am a female and because both I, Tallis and my female Hawke have breasts, I must feel threatened by Tallis and her successes when my PC is not allowed to succeed. Yep, I am totally jealous of Tallis. That's why I hated her character. Thanks, Gaider.
Then, to complete it all, the one thing I loved about DA2, the wonderful companions, are getting tainted by revelations in comics years after the game's release. I do not even read the extra material, as I consider it milking of the franchise and refuse to support it after DA2, but because I frequent these forums I stumble into threads about it, and what I learned there about Isabela's past is pretty impossible to forget or ignore. She was one of my favorite characters in the game, but The Silent Grove turned her into a giant lying hypocrite and her friendship or romance with Hawke in a lie. And of course this is again just on me, that I thought I knew the most important things about the character after playing DA2.
So... sorry about the rant
, but I can't say I'm very impressed with Gaider post-DA2, both due to his work and his tendency to resort to snarky replies.