All typologies are reductionistic - even one as complex as the DSM IV. Their utility is in guiding research and theory, in organizing observations so that commonalities can be found in otherwise disparate observations, and in allowing some consensus in terminology and communication.
Students tend to gather information reductionistically, trying, I think,to fit the new into their existing "apperceptive mass". Giving them "types" gives them something to hang the new information on. A student of human nature, however (i.e., a lifelong observer of human behavior), increasingly comes to appreciate the unique, individual nature of each person...creating many branches for their tree of knowledge.
I have one issue with harkening back to Adler's (and even Ansbacher's)writings for "the authoritative word". I'll put it in the frame of a question.
Does Adlerian theory evolve?
It seems to me that current cognitive-behavioral/ constructivist/narrativist approaches to therapy are an evolution of Adler's observations...
And further, that (in contrast to something in an earlier thread) it is not that current theory is becoming more Adlerian, but that current theory stands on Adler's shoulders, (as well as those of others.)