Very nice. I disagree with not going to recorded ones. When is the time to watch recorded talks: never. So it is now.
And the 5 minutes talk 17 min discussion could work, but it really depends on the company. If head of e. g. darpa gives instead of a 1h keynote a 15 min teaser and then all 1000 participants can start discussing, it might not really work (as other situations as well).
Beyond the scenario you describe, I have some apprehension around audience questions in these venues, as the questions are often enough digressive or part of some dominance/status game.
For a speaker to aim for presenting for 25% of the time and fielding questions for the remaining 75% strikes me as lazy or a dodge in case you have no idea how to effectively present your information.
Totally agree with you on the recorded talks, BTW!
And the 5 minutes talk 17 min discussion could work, but it really depends on the company. If head of e. g. darpa gives instead of a 1h keynote a 15 min teaser and then all 1000 participants can start discussing, it might not really work (as other situations as well).