Well...
Gay Marriage - This can be done in Skyrim. Right now. Without mods. ME3 also allows for gay relationships, though no marriage either way. This does seem like something that should be included in the next Sims game, though.
Torture - I played 4 missions of COD Black Ops (no online, thankfully) and it seemed to me that they were beating this Mason fellow up pretty badly. The protagonist in the new Syndicate remake wakes up being beaten half to death. At one point in Rage you ate captured by hostiles and almost killed. Aside from Mason in BlOps the gaming coverage of Torture seems pretty brief, but is has been covered. To be honest, the main reason I quit playing BlOps before at least finishing the campaign (Side note: It's amazing how fun that game is when you play it singleplayer!) was because the torture made me squeamish.
Abortion - What quote said. The number of games with marriage is small. The number of games with kids is, AFAIK, singular. Besides The Sims 3 (and maybe The Sims 2, I skipped that whole iteration) I can't think of a single game that includes pregnancy at all. That said, yes, this seems to be to be something that the next Sims really should cover. Knowing EA they will avoid it like the plague, but I can't think of another game that is even in the right realm to cover it. They don't even have to call it Abortion. They can call it an "anti-woohoo potion" for all I care.
Nihilism - Again, what quote said. Unlike the other 4, this has actually been covered ad-nausea by a myriad of games. My assumption here has to be that what you're looking for is a game where the protagonist, rather than the boss baddie, has this. I can think of a few (still haven't seen the grand moral justification for everything Mercer does in Prototype, for example) but clearly this motive is indeed very lopsided towards the bad guys, and the player is seldom the bad guy. As I understand it (haven't played it) Saints Row has this to a certain extent. I mean, you're playing as a gang member trying to defeat a rival gang for no other reason than "this is our block, fools!" and that's pretty much the most paper thin justification I can think of for dropping JDAMS on civilians in LA from an F-22. This isn't exactly protagonist-nihilism but it's in the same family.