This is not a discussion about the general rating system and Skyrim's Mature rating, this is about what "Mature" means to you, the player. I think Skyrim lacks some mature content (quests that bring you to face very strong moral decisions, storyline branches that lock/unlock special events based on your previous choices so you have to live with serious dramatic consequences and know that what's happening now is your fault only, etc...).
Skyrim gives me this impression that it's designed to aim @ teenage public with all the simplistic dialogue, black and white choices (when you actually are given a choice and not forced to be good or bad), lack of swearing and sixual content, lack of blood when someone dies, lack of horror aspects that creep you out not only with cheap hollywood techniques (ie spider jumps on your back), but with things that you didn't expect to happen, atrocities, extreme violence and graphic/audio representation of extreme fear or pain...
In this game (and oblivion suffered from this too) there is a perceivable concern to be "politically correct", to be as appealing to the crowd as possible, at the expense (at least in my opinion) of credibility and atmosphere. Beggars are healthy and athletic, not dirty and crippled. Nobody dies in front of you from hunger or infected wounds. There is no domestic violence for the player to witness. The prison is clean and quiet like a hotel, not full of tortured prisoners, blood, swarming flies, corpses, rats and screams. The whole story and atmosphere is meant to make us believe there is a serious civil conflict and a world breaking threat going on, but the towns and especially people are way too calm and ignorant to make it authentic, to make you really empathize for their suffering. I think the storytelling and the dialogue play a major role in making this game comfortable to the player, and I think too much comfort hurts credibility.
My question is: are you satisfied with the maturity of Skyrim? What would you like added/removed so it feels and play more mature for you?
Initially, developers set out to put those details into a Video Game. But it just is not efficient right now. Video Games are not movies. The things you mentioned appear in movies all the time. But a Video Game, again, is not just a visual experience. Skyrim is a monumental feat of visual, audio, story-telling (all those books), programming, and etc. and etc. This game would have launched around this time next year if they polished everything. And by that time, the games visuals and etc would be dated.
So like I tend to say, when it comes to these threads where people suggest how Skyrim "should have been", your answer as to why it isn't does not lie in the lack of Creative Design talent on the Bethesda team, but rather the time constraints, and the budget of the project.
I rather have 100 different dungeons and areas, rather than a couple well detailed "mature" areas and features. This is a fantasy adventure game, have you seen some of the dungeons in this game? Some of these dungeons aren't even part of the main story quest but their are absolutely unique and stunningly beautiful!
Bethesda didn't set out to make the Witcher. And I'm sure you can get what you want if you post this in the mod section of the forums.