My school does the line up by rank and bow thing at the beginning of classes. I don't mind it because I've found out for myself that the guys to the right of me deserve to be there.
In a typical class we do about five minutes of hard warmup, go over a drill for 10 min, roll for 15 min., drill for 10 min., roll again for 15 min., then cool down. After class I stay for 1-2 hours of Randori.
I'm curious if other people's schools have different classes for beginners. Until we get our 3rd stripe (about 6 months, 3 times a week) we have a special class that has a lot more drilling then the regular class. The idea is that beginners learn basic techniques and how to control themselves before they get to do a lot of rolling. I've been in the more advanced class for about a month now, and I'm really glad I learned the basics first. I feel I'm pretty equal to the blue belts in my school, and once in a while I'll surprise a purple. :)