Because I can't not: Oghren doesn't make real progess in Origins. He's basically enabled to the point where he thinks he's past what has happened to him, so he moves on with Felsi way too soon and convinces himself that being a hero is good enough. But it's not- the underlying issues (abandonment, anger, PTSD) are still there, and being a respectable married man can't change that. So he joins the Wardens, which is a one-way ticket away from the domestic life he's failed at and a death sentence with fighting, to boot. His "reset" in Awakening is realistic in that he needs more than someone who throws alcohol at him and bolsters his self-esteem- he needs to work through all the issues he brought up with him to the surface. And, given that DA doesn't seem to have AA or therapists, chances are he'll never be the Oghren he was pretending he could be at the end of Origins, but he can at least do good and maybe not destroy everything worthwhile in his existence. It's a complicated and frustrating character arc, and probably not what was intended before he was forced into Awakening, but it's one of my favorites in DA.
Relating this back to the topic, one of my enduring frustrations is that people argue that playersexuality destroys character agency, or natural character growth. However, characters like Oghren, who bucked the trend in Origins by not being a companion that could stay "saved" by the Warden's pure force of charisma and bottomless gift sack, tend to get a ton of blowback for not being malleable enough, or not conforming to the player's expectations and efforts. For all people talk about not wanting their PC to be the center of their companions' lives, they tend to get up in arms the moment that something implies that they aren't.