And to give a perspective from Sweden and the Swedish Rite I can tell you that we have recently lowered the time from 1 year as EA and FC respectively to 6 months for each degree if the brother is sufficiently active. Here almost every lodge meet at least once per month, and the big lodges meet every week so every EA and FC can go to lodge and see his own degree several times before he is passed on to the next. I personally believe it was better when you had to wait one year instead of just rushing through at 6 months. For me a few weeks or just a few days is an unbelievable fast progression.
The reason we take time for each degree is that the lessons and intricate symbolism have to be integrated and understood before you go on to the next. At least in the Swedish Rite each degree builds upon the ones before, so if you just speed through the degrees there is a great risk of not understanding the whole picture once you are at the top. By having a minimum time in each degree (and the minimum time gets longer and longer for each degree) the brother will have time to reflect on what he have been taught and also see the ritual several times and study the details before he progresses. Once he is a MM he can directly become an officer, but on our system there is no requirement for that.
Also, the Grand Lodges working with the SweR require that all business are conducted at EA (for the St Johns lodges at least, the system is a bit more complicated than that
)
EDIT: Sorry, I didn't noticed I posted in an old thread. I hope it's alright