As to the phrase "Revamping of a classic Christian vocabulary," would you say it is an example of an uncountable noun turned a countable noun? Surely, I don't think we are talking about revamping of a single Christian vocabulary (or word). but instead I think we are talking about revamping a whole collection of words in the language a person uses.
Vocabulary does not mean a single word in any case; it is a set of words-- or as you say, a collection of words (one collection, two collections). I don't know which came first, the countable or the uncountable.