It could be handled better for sure, I have a few suggestions for future events:
-Unlock everything a month or two later for everyone. Playing the event just means you get it earlier. That way if there's any bugs or people have no time to play it, they will still get the new stuff.
-No more filler stuff. Keep the rewards actual rewards, new stuff to unlock. Not anything already in the game like satisfaction points, money or potions. I could honestly do without the collection stuff too since the game already has plenty and I'd like more interesting ways to collect new collections than this. This could also allow the events to not overstay their welcome. No need to spread out two weeks of content over four weeks like this latest event did.
-A surprise reward at the end. This would make the ending so much more satisfying, and would help to get players more invested in it. Like this search for the time traveller was such a whole bunch of nothing in the end which was a shame. Would have been so much better if a well known classic character was the time traveller, we'd see them in the end and would unlock their outfit or such without it being listed in the event rewards. Like it could have been Marky Sharky, and you'd unlock his mascot costume which would also appear under swimwear. Wearing the outfit could let Sims perform his dance. Could also be an object. Sims 3 had a time machine sims could build after all and could use for rabbit hole adventures. Would have been perfect for a final reward of the event.