I agree with the sentiments that teens need to be fixed. They definitely need more teeny interactions and milestones. For me, I just seen preteens and teens as having very different milestones and maturity levels, so I think the game has room for both.
For example:
Preteen (ages 10 through 15 for the sake of this discussion) milestones to me are things like getting your first crush, hitting puberty and getting break outs, body odor and voice changes. (Can you imagine how cute it would be if your preteen sims voice cracked every now and then through the lifestage, maybe resulting in an embarrassed buff depending on who they are talking to?) Going on chaperoned dates, first school dances, crazy mood swings, beginning to gain more independence and going out without supervision. Growing out of certain friends as your personality changes, and making new ones. Gaining more responsibilities at home, such as weeding the garden and cleaning the kitchen up after meals. Preteens represent that tender, awkward age to me, where you're still fairly naive and innocent, still have a lot of maturing to do, still more childlike than you realize, but you're just so desperate to hurry up and be grown already. All those hormones are kicking in and have you feeling so odd and irritable, but you're just so sure you're ready to be treated like an adult.
Teen (ages 16 to 18) milestones to me are things like going on your first real date, your first relationship, learning to drive, getting your first job, discovering what you have a passion for in life. Your first break up, getting to stay out later, sneaking out, homecoming and prom, more peer pressure to become woohoo active, drink hard juice at secret parent-free parties and maybe partake in some underage bubble blowing. You still have mood swings, but not as intensely. You're a little more level headed and sure of yourself, and starting to feel more confident as you grow into your body. Your brain is shifting closer to adulthood. Teenagers, to me, are very much like mini adults in reality, so it makes sense that they would be so in the game as well to an extent. Yes, they are still just kids, but they are right there at the door to adulthood and the focus for most parents of teens that I know is preparing their child for life in the real world, which usually means gaining the responsibility and life experience needed to be a successful, independent adult.
I think having the ability to ground teens/possible future preteens, and perhaps a time out interaction for toddlers/child sims, is a necessary interaction particularly if they aren't going to set a curfew for minor aged sims in game. I think it would enable more players to feel like they are actually parenting their in game children rather than it feeling a bit like TS4 is some hippy oasis where kids never act up and there are never any consequences for bad behavior and parents are really just friendly roommates that do all the cooking, cleaning and bill paying with zero expectations or rules.