For the same reasons, I suggest banning them here as well.
On the first, the usual convention here is to tag a question about a specific book with the name of the book. Early on, there was a problem with hebrews because someone had already created a hebrew for the language and the SE engine automatically created a synonym between the two. This was fixed so that we could continue to use the name of the book as a tag. I think that convention makes clear that john is the book and not a person. (The other books named John are (or will be) tagged 1-john, 2-john, and 3-john.) Banning john will increase confusion here.
On the second, tags ought to be interpretatively-neutral when possible. That means we should avoid tagging question in ways that presume an answer. Some questions will turn on the meaning of the word "church". Is it intended as a universal movement or as a local group? Encouraging the questioner to presuppose one or the other seems a mistake to me.
More importantly, we avoid questions of doctrine here and therefore the "global church"/"local church" distinction is much less important. On Christianity.SE, the distinction matters a great deal since some doctrines are applicable to one and not the other (maybe ;-).
(I'm not expressing myself well on this point, but I don't think we need to ban church since Biblical Hermeneutics focuses less on the Church and more on the texts. Does that make any sense?)