I think you're wrong. I think "coming of age" (when used metaphorically) expresses part of the idea in that German word and other English words and phrases express other parts of it, including "education" ("In today’s German language, Bildung very often refers to no more than 'normal' education").
I think the assertion (made by the previous poster) that "picking one language may be limiting what can be expressed" is wrong. The fact that there's no 1:1 translation for bildung in no way implies that the meaning behind that German word is inexpressible without taking it as a loanword. In fact, the article you linked explicitly translates the idea into English in various ways that are totally comprehensible to an English speaker: "self-cultivation," "maturation," "unification of selfhood and identity within the broader society," and so on.
You didn't explicitly deny it but the previous poster raised the possibility: "picking one language may be limiting what can be expressed" (this is Sapir-Whorf). I thought you gave bildung as an example of something that cannot be expressed in English but I may have misinterpreted you.
> Of course English speakers can talk about the concept using circumlocutions or using a number of overlapping concepts.
I don't see any circumlocution here but that aside, you seem to agree that picking one language does not limit what can be expressed.
> But the concept Bildung is not central to Anglo-Saxon pedagogy or education, that's why you don't have a real word for it.
I understand there's no exact word:word translation. Anyway, I think the concept expressed in bildung is not specifically German, I think it's related to the concept of education in general, specifically to the idea of an education that produces an individual who is simultaneously part of a collective and fully himself, an integrated individual, someone who who can appear in public and take part in discourse and also contemplate on his own. That goes back to Plato and, I'm sure, earlier. Another English word we use to express this is "civics".
I think the assertion (made by the previous poster) that "picking one language may be limiting what can be expressed" is wrong. The fact that there's no 1:1 translation for bildung in no way implies that the meaning behind that German word is inexpressible without taking it as a loanword. In fact, the article you linked explicitly translates the idea into English in various ways that are totally comprehensible to an English speaker: "self-cultivation," "maturation," "unification of selfhood and identity within the broader society," and so on.