To be fair, I don't really see a need for preteens, what I do need is more teenagy teens with interactions that are more in line with their supposed age. Where is the screaming and slamming in doors? The staying out late at night even if you're not allowed? I miss the hang out option and I want teenagers to have clothes and hairstyles that are reserved for them and with a needs decay that is unique and phases that are unique too.
With that said, I do feel we need one more age, just not preteens. For me the missing age is middle age. Where you can no longer have kids, no longer look 35 (more wrinkles, thinner hair, easier to gain weight). Complete with various mid life crises-phases and stress over not finishing life aspiration.