Yes, the change to "head of a pin" misses the point, as you say.
To continue in the same spirit as those medieval theologians who engaged in lengthy and somewhat pointless disputes, I have to say I'm not sure I can agree with Peter Harrison's claims when he says:
"the first reference to angels and the points of needles, which appears in an expository work by the English divine, William Sclater (1575–1626)"
and
"The examples cited by Sclater are all genuine topics of scholastic disputation except the last" [i.e. "How many might sit on a Needles point"] which seems to have been introduced solely for its rhetorical value as a clever pun".
You see, in a late collection of the writings of the 17th century Dutch theologian Johannes Braunius published in Amsterdam in 1700, in a passage castigating medieval theologians for the many "absurd, ridiculous…questions" ["quaestiones…absurdae, ridiculae…"] they liked to grapple with, one question that gets an explicit mention is "quot angeli possint contineri in puncto acus"- "how many angels can fit on the point of a needle."
If Harrison's claim about the "first reference to angels and the points of needles" being Sclater's is correct, then we would have to assume that Braunius, active in the second half of the 17th century (i.e. only a few decades later than Sclater) and publishing, I believe, solely in Latin, included the question about angels on needles not because this was a question medieval scholastics had a longstanding reputation for asking but simply because he'd read Sclater and lifted the passage from him; either that or Braunius miraculously made the same invention independently of Sclater.
Harrison also appears to have missed the reference to a "thousand angels…on the point of a needle" in the 14th century mystical work mentioned in the Wikipedia article.
Lastly, although the transition to "head of a pin" from "needles point" is a pity, there is nothing wrong with translating Latin acus as pin, since acus can mean both pin and needle.
Edited By Bill Phinn on 29/01/2020 02:58:45