I like surprises and all that jazz-- but yea mechanically speaking it makes more sense to show off all the pretties from the beginning so I can plan my shopping x)
Having the last of the items release 1 week before the end of the event felt punishing to me. I am a procrastinator, but why should the site punish players who want to get the event out of the way with? Why should players have to hoard all their tickets until 1 week left just to be able to properly plan out their purchases? The battle pass is probably how most players get the bulk of their tickets, so it's not feasible to spend all your tickets, finish your battle pass, and then have to grind out even more if you ended up really liking the last set.
I guess I was just really neutral on the event, TBH! I thoroughly enjoyed the Murkwood event, and honestly didn't mind items being added later on simply because I like the grind/challenge of grabbing stuff and earning tickets, though I totally see where other people were coming from in regards to saving/spending tickets and wanting to plan their purchases.
Maybe, if new items were to be planned to be released later on in the event, the staff could put in placeholder icons and list the prices of the upcoming items to maintain the mystery while simultaneously allowing players to know how much to save up for the later releases? And then, you know, either list the availability date or make a news post to alert people.