I seem to remember that Meredith's mom was/is involved to some degree, but not in any role that has input into who makes the squad. Shelly doesn't either. She's more involved then Meredith's mom, but, again, not in a role that has input into who makes the squad. While all three girls might have had some maturing to do, Dayton had improved measurably in the maturity department between her first audition and her second, but Kelli seemed to REALLY hate the fact that she was even there, much less in Training Camp.
I totally agree that Cassie could have used at least one year, possibly two, on another team, especially one that's dance-heavy, and she would have proved to EVERYONE that she deserved to be on the DCC. If she had gone off to another pro squad for a couple of years, then come in and blown everyone out of the water, no one could argue that she deserved the honors she got afterwards. While both Victoria and Dayton may have had issues, any one of Victoria's issues her first year would have knocked another girl out much sooner and the lies would have gotten said girl blacklisted, never to make the squad, yet she not only makes Training Camp the next year, but the squad AND Show Group (she at least should not have made Show Group). Dayton was late ONE time through an issue she couldn't have foreseen, though she could have left sooner knowing traffic in the Dallas/Fort Worth area. If Dayton was late multiple other times, then I'd say she has a time management issue. However, ONE time should have gotten a reprimand and left alone after that. As for the rest of the issues, how many other girls had power issues and memory issues, but made the squad? If Dayton had been given the opportunity to have at least one year on the squad, she would have improved beyond all doubt and been a star DCC. I still think Kelli did NOT want Dayton on the squad and was doing everything in her power to keep her OFF the squad.
While Cassie was at best a blender, I think she rested on the fact that no one was going to be allowed to cut her because of who her mom was and the fact that many of the judges have watched her grow up. Thus, she got away with more then the other girls and caused more problems.