I completely agree with you about the Halloween event. I wasted so much time and money.. and for what, a piece of candy? A piece of candy i never even used.
Your suggestion for Christmas is better but I wouldn't want it to be the only event- it's certainly not for everyone.
(Which is also what I didn't like about the Halloween event- only people who like to spend 30 minutes on a single monster for a piece of candy could enjoy an event like that.) Not everyone likes to MVP. And well, monster invasions don't really seem appropriate for the holiday.
I think something more related to gift giving, questing, and random spawning santas (antonio?) on field maps that drop gifts, equips, and candies would more so suit the spirit of Christmas.
And with all these new GM's, it'd be nice to see some creativity coming out of those in charge of events. Just a suggestion. :)