However, their rantings do not mimic "inspired expressions" as recorded in the OT and NT. They have the ring of personal opinion, rather than inspired utterance.
I think Paul's letters often come across as something very personal and opinionated rather than inspired, and once or twice he even says that he's giving his personal opinion. He goes on a rant about his annoyance at women speaking up at meetings. At one point he brags about how many trials he's gone through as an apostle, to try to exert his authority over the congregation he's writing.
Since Paul was part of the first GB in the eyes of the Society, one could say that they're only following the example he set for them.
I perceive Loesch as subdued and foreign. It is also apparent that we Americans are easily gulled by EU accents.
It's not really clear to me that Knorr was a dignified speaker. I'm not sure I've heard him speak, but people mostly seemed to just find him staid and boring. I've heard Franz speak, and he sounded like a kooky Bible nerd. So I'm not sure how you define "dignified".
To be more specific, regarding my allusion to corporate decorum, I would expect them to police themselves, and each other, lest they appear foolish. Don't they have press-agents or aide-de-camp that prevent them from committing a faux pas?
I would imagine they try to police each other, but they have no authority over each other (unless the entire group were to side against one or two members). If you've ever been stuck working on an assignment with an idiot for a partner, you know the hell of wishing you could do something about somebody but being powerless to change anything.
As far as personal assistants who can give them advice, you're forgetting that these guys were COs and DOs before they were on the GB. You try giving a CO counsel on one of his talks and see how that goes for you. I can't imagine someone saying to them, "Okay, now, Brother Morris, let me read over this script before you deliver it."
This shouldn't be surprising. Rather recently we had a Texan yahoo for a president. All the king's men and all the king's horses could not stop him from sounding stupid and folksy. And you can be sure that presidents have a coterie of image management people working on them constantly. There's some evidence that Bush did in fact learn to speak much better as the years went on, but as a presidential candidate he was a linguistic train wreck. Despite the fact that he had people writing his speeches, he often refused to stick to the script, preferring to extemporize. And Bush was probably on much less of a power trip than the average GB member.
I would also like to see some specific, scriptural, proof of their claims of Divine Authority.
I'm not aware of any specific basis for someone becoming part of the GB; it's not like there's criteria to be met, like when someone is sainted by the Catholic Church. The assumption on the part of JWs is that, after years of faithful service, the GB consider the qualifications of their helpers, and using prayer they are guided by the holy spirit to make the right decision.
Of course the GB do not have any miraculous evidence of their authority or approval by God, but they point to the accomplishments of the org. and the "spiritual paradise" of Witnesses as evidence that they have God's blessing. Remember that the NT says that gifts of healing, etc. would cease in the future, so expecting them to bring forth water from rocks is contrary to the Bible.