I don't think it would be a bad idea for the rating to change....however...Ea is thinking about money therefore they won't change it. They know we can have mods or create them ourselves to create hacks to make our own games a higher rating. They also know that it would lower their sales because a lot of teens and younger buy and play the game.
Those that are too young to work, or just don't want to work...they know their parents buy a majority of their games and not 'many' parents would support a M rated game.
I do think some things could be incorporated into the game, and it still keep it's T rating.
I think teen pregnancy with 'consequences' like having to drop out of school or still stay in school yet try to take care of a baby. Maybe the parents put them out if they get pregnant or even if there is a pregnancy, maybe the young couple stay together and work things out...but it still not be an easy task. They have to work to take care of the baby and show that it's very expensive raising a child. Have a scrutinized or shunned type of action. Just a few goofy ideas...but I think it could be incorporated into the game without much hassle.
Since they do have gambling...(and I'm still trying to get that darn Casino!! Just still too much money to spend on a sp!)
...and they have drinking, smoking what looks like a bong and some of the dancing could be seen as maybe a bit, adult'ish.
As they have these things already in game, I think there is room to add more. How about teen drinking and they get caught by the police? That would be a cool thing or better yet...make it so they are arrested and they call the parents to bail them out and give the option of whether or not the parents post bail or make them spend the night in jail.
Just a few ideas off the top of my head.