You were given 2 weeks to prepare with a tag from Walross, and a tag 6 hours prior to being able to talk to the NPC. Please tell me that isn't enough time for you to get ready.
My timezone is EST, and I was perfectly fine. Please don't make it like you're speaking for every single person who's in that specific timezone, since you said, "the catch times were ridiculous for players in EST timezones."
I don't understand why you waited for a few days to make a thread like this, which really isn't suggesting anything, it's more of a complaint. Why didn't you make a suggestion thread before the gen 8 legendaries catch date, so that at least, "ThEy cAn dO A bEttEr jOb", or on a more serious note, look at the suggestion and reconsider, putting in more times, making it last longer, just as an example. Making a suggestion now and suggesting them to do a, "bEtTer jOb iN fuTuRe eVenTs" isn't going to help anyone, come on now.
Okay, let's say, for the sake of my argument, whoever's in staff that is in charge of creating and setting up the times gives us another chance and an additional date where you can catch Zacian or Zamazenta. Wouldn't that be unfair to the people who tried to get on during the first two times? People who woke up extra early, or people who got their devices ready and camped near the NPC beforehand, and simply logged in and spoke to the NPC so they can do it later. You ever thought of that? You don't actually have to answer the question, the answer is no.
Just like outbreaks and world quests, there's always going to be a bad time for someone. It sucks yeah, I know, but that's just how it is. You can make a new thread on what you think of World Quests, but my point here was, there is never going to be a perfect time.