One thing I like about the Millennium Girl pre-teen is that she's flat-chested.  This makes her look younger than Laura, so she fills an age gap in the generation 3 line. 

I wish they'd given Laura a "chest flat" morph, though.  That would make her considerably more versatile. Yes, you can do it with magnets, but if they'd made it a standard morph, it would be a lot easier.