Just knowing a very minuscule about the tech that goes into running a website - especially one as complex as the DVC site - making a change as "simple" as adjusting the gate time for when reservations can be made/modified likely requires a massive amount of backend changes/coding. On a normal day, a change along those lines is likely incredibly complex, not to mention during a holiday when they're likely running on a skeleton crew and the priority is likely just getting the page up and running.
Also, if they were going to announce a time to "relaunch" the site, my guess would be that they'd simply announce 8:00 am on 12/2 (rather than recode for a new start time on 12/1). And if they did something like that (basically suspended the reservation system for a day), it would have likely compounded the problem with an even greater amount of people flooding the site at once.
Totally get the frustration - we were frustrated too as we tried to make a reservation - but unfortunately there was never a solution that would please everyone. Yes, they technology should absolutely 100% work but today just happened to be the perfect storm of issues - the website crashing during one of the most popular booking windows of the year on a holiday when member services is closed and IT support is likely at a minimum.