I would propose that maturity is tightly interwoven with how much a game is willing to commit to the seriousness of its own world. If that is the case, then I find that while both games have very mature elements (a politically motivated plot, characters with believable personalities and motivations), both also suffer from immature elements, albeit in different ways.
For "The Witcher" series, my problem is in the NPC's. With consideration of the the medieval backdrop where the game takes place, I find too often that the majority of the NPC's (human, mostly) are bumbling, immature fools. The world "plough" as a sexual expletive is used so often that I think I'm watching an episode of Deadwood. BUT, and I stress, BUT...this is not enough to call the entire game "immature". Everything fits into the context, so I would call "The Witcher" series very mature (aside from "lesbomancy").
For "Dragon Age", I find the NPC's more believable by comparison. They're focused less on being assholes and more focused on specific tasks (a balance between rationality and irrationality). There was a little too much focus on sexual exploits in the second game, but the first handled sex tastefully (albeit, with more clothes). My problem is that the violence in "Dragon Age" is immature (it is). The actual gameplay was fine, but the bloodstains and the impossible feats of athleticism reduced the emotional impact of the violence. But these elements are never addressed, as if the characters refuse to acknowledge it, or it's some kind of joke we, the player, aren't in on. Aside from that, I still find "Dragon Age" very mature for its thematic elements (aside from "apostitutes")
For "The Witcher" series, my problem is in the NPC's. With consideration of the the medieval backdrop where the game takes place, I find too often that the majority of the NPC's (human, mostly) are bumbling, immature fools. The world "plough" as a sexual expletive is used so often that I think I'm watching an episode of Deadwood. BUT, and I stress, BUT...this is not enough to call the entire game "immature". Everything fits into the context, so I would call "The Witcher" series very mature (aside from "lesbomancy").
For "Dragon Age", I find the NPC's more believable by comparison. They're focused less on being assholes and more focused on specific tasks (a balance between rationality and irrationality). There was a little too much focus on sexual exploits in the second game, but the first handled sex tastefully (albeit, with more clothes). My problem is that the violence in "Dragon Age" is immature (it is). The actual gameplay was fine, but the bloodstains and the impossible feats of athleticism reduced the emotional impact of the violence. But these elements are never addressed, as if the characters refuse to acknowledge it, or it's some kind of joke we, the player, aren't in on. Aside from that, I still find "Dragon Age" very mature for its thematic elements (aside from "apostitutes")