How about a livestream and/or recording of the whole meeting? Bitcoin should not be about closed meetings.
A written contract that confirm that you all agree for a same direction, handsigned by everyone would a good idea I think. I least we would know that tommorow another new idea will pop up and create again a big mess.
I'm pretty sure that it would be very hard to reach an agreement with 70 parties involved (in a limited amount of time), especially when there is some support for the other side of the argument (political debate - power grab).
Look at the 10 minute block time restriction. Whatever you do with SegWit ( which is brilliant ), or with blocksize changes, you will still be looking at up to 30 minutes for a confirmation. That's a long time for an on-line service these days.
Wrong, this does not usually happen. My transactions have never taken more than 10 minutes to confirm, unless there was unusual block timing.