It seems like a good FIRST/Engineering class might have different supporting modules. Maybe a section for CAD, a section on programming, a section on electrical, and a section on mobility and functionality devices. I think this would be good, then let the students used what they have learned to package it all up in a robot in January. I would teach the elements before hand, but hold off on the actual robot building until January. For each section of this class, I would give some good instruction to get them moving along but not enough instruction to where they master it. After the formal instruction period, I would assign them a final project (preferably in teams) that builds on the skills they have learned. Make the project seem like it requires more skill than they have, and make it require techniques they don't know how to do. With the basic instruction from the teacher, then independent exploration by the students (with assistance from teacher as needed), the students are sure to learn a great deal and the whole program will be a giant success.
Most of all, in any class of the sort, it needs three things, challenge, competition, hands on experience. I would also say fun, but that is a given.
