The Scriptures written by the apostles, however, don't show particularly poor grammar, and in many cases is of the highest quality. Even simpler grammatical forms such as one finds in John is of a lower register, not a lower quality.
Moreover, Paul didn't confuse anyone due to his proper use of language. He was confusing because of the subtlety and nuance of the concepts in which he was working.
That's my take, anyway.
I don't mean to suggest that everyone needs to speak (or type) in a high register. Formal word word order devoid of colloquialisms and common idioms can be tiresome and even pedantic, especially in a discussion. Good grammar doesn't mean formality; it means making language clear through the use of proper punctuation. Now of course, there are debates over what constitutes clarity (for instance, whether to use the Oxford comma), but these debates are between people who understand that grammar is there to clarify, not to confuse.
An example using the Oxford comma:
If you leave out the Oxford comma (a comma that precedes "and" prior to the final item in a series) you can create serious ambiguities. Thus, "My usual breakfast is coffee, bacon and eggs and toast," can mean either "My usual breakfast is coffee, [the mix of] bacon and eggs, with toast" or "My usual breakfast is coffee, bacon, and eggs on toast." By putting a comma before the last item in the series (whether "eggs and toast" or just "toast") you remove ambiguity which can confuse your readers. It's not necessarily formal; it isn't ostentatious; it just helps clarify one's meaning.
Another example, this time using words:
"To lie" in the sense of "lie down to sleep" means that you, the actor, have performed the action of lying down to sleep [the verb is intransitive]. "To lay" in the sense of "lay down to sleep" means that some other actor has put you into bed [that is, the verb is transitive]. This is simple enough, but it gets confusing before the English language has evolved in such a way that both words change in overlapping ways depending on the time referent. The past tense of the present verb "lie" is "lay," and the past tense of the present verb "lay" is "laid." If you don't know this rule and you're writing about, say, Jesus in the tomb, you can see how you might paint a confusing picture of who is doing what and when without properly expressing yourself.
Anyway, that's why we created this thread. There are already enough problems with people understanding each other, whether in politics or, especially, on this forum. No need to let deficiencies in actual communication get in the way of healthy debates.