I have to agree with Fr. Ambrose that a perfunctory confession is not necessarily meaningless.And I have to disagree with you both. I think it is legalism.
And you're entitled to your opinion.
However, I have been participating in group confessions for decades now, and I feel very differently. I have always found it very meaningful. The confession that is read is pretty detailed and, by kneeling in front of the altar, you are adopting it as your own. You end up confessing to a lot stuff you probably wouldn't think of on your own during an individual confession. That's just how I feel, though. If you want to judge me and say I'm being legalistic, or that I really haven't been absolved of my sins all these years, that's O.K. People have said worse to me.
You are not the only one, however, who is critical of group confession. As I said, it was an accommodation that was made after most of our clergy were wiped out after the Genocide. There are priests who would like to bring back individual confession. Maybe someday that will happen.
I notice you and Peter are putting a lot of emphasis on the amount of minutes the confession takes. I can't understand how that matters. To me, that would seem like a legalism. Who are you to say a very sincere penitent can't express himself in a short amount of time? Especially when the confession happens often, I would think the amount of time for each confession could be less. I don't know. I just think that is a judgement best left to the person's spiritual father.