Without buckets it would be nearly impossible for people with credit histories under say 12 years to get loans at the best rates. Should everyone have to wait to hit 35 before they can get a mortgage they can afford?
FICO scores are not about what you have done in the past - though that is the information they use. They are about PREDICTING whether you will default or be majorly late on payments over the next 2 years. Buckets allow FI to sort people into like groups and determine which of those are likely to have credit troubles and which aren't likely.
Much of the details on the buckets are not public knowledge, so we cannot have a debate on the details. As someone with a spotless but short history, I am glad FI has buckets because I am able to stand out over other young credit consumers and that distance is reflected in the FICO number (without a manual review).
Bucket moves rarely effect people for long, though they aren't fun. Unless you are applying for a major loan in the few months after a rebucketing you should be fine, as your scores should rebound quickly. That is why we often say don't get a lot of new credit before a mortgage loan or an auto loan because it may rebucket you and we can't predict what that will do to someone's score.
