I don't agree with you about the wet pit. It isnt that hard to dry off your hands and pole and grab some more chalk. If you use stickem, there is no issue there either.
I agree with what you're saying about advancing the field at trials, that would have been smarter to do what you described. It would have been the fairest way to deal with it in a safe manner. One or two extra jumper in finals isn't a big deal.
I know some meets keep vault running in the rain (for example the decathlon vault in 2012), but in my opinion that is dangerous, I have and will continue to pause or cancel vault at meets I officiate if it is raining.