I did the Early Bird clinics. They were fun, entertaining. But you can't just take that into a race. We did a "cornering clinic" and the race immediately following had bad cornering throughout. Go out and descend high speed and you figure out cornering real quick. I think a few things are great to keep in mind first race: follow the line, don't cross wheels, bumping won't hurt you. But just being told these things? Or practicing once in a mandatory clinic? That won't help any more than the first cat 5 race will.
I got to do bumping drills one time - a while before I ever raced - on pavement, low speed. First bump and I was never scared to bump again. It was useful just to prove bumping won't hurt. But I still don't think there should be more barriers to entry.
Also I think it's a good point that others brought up - that's what cat 5 IS. You have to pass so many races before entering the sport as a cat 4.