Couldn't think of better ending than the old "it was just a dream"?

Actually it wasn't a dream it's been confirmed in the commentary that they did in fact go through all the stuff they did. However the ending can be several other things. Some say they were spared because of Max offering to sacrifice himself at the end and that Krampus is now watching them all (he sees you when your sleeping he knows when you're awake) to see if they keep the true spirit of Christmas. They all remember when they see the bell max receives as a gift from someone unknown. Where as some people theorize that they are in Hell spending eternity on Christmas morning "I just wanted Christmas to be like it used to be" and that be bell was actually Omi's gift to max. Notice at he end Krampus has tons of houses in globes but nobody knows yet if those are family's he's taken or those that he's watching.

There's one more theory that I like floating around that the story is actually about a family trapped in a blizzard on Christmas and the rest of the town was evacuated and that they are all dying of natural causes and that Krampus and his minions just represent death.

Wow, you didn't get the ending at all.

It was not a dream at all. It was just Krampus pushing the reset button.
It was clearly stated that Krampus his job was to teach the christmas spirit by punishment every time a child loses hope severely enough.
However Max had his hope rekindled when he realized how much he would miss his terrible family.
So Krampus knew that his job was done and he gave Max exactly everything he needed to have a better christmas.
Omi didn't learn, but Max did. And somehow Omi learned after all, thanks to Max.

Lol that's not what the ending was at all...

It wasn't a dream. Everyone is dead and trapped in Krampus' hellhole.

Yes, I know it wasn't literally a dream. But you still had the main kid wake up with little or no memory of what had happened. Maybe not a dream per se, but a dream-like situation with fuzzy memories. And it's not like he went into the living room and everyone explained it to him..or he explained to them what he's been through. No, they were sorta-kinda all vague and la-la land, just like a dream.
Did Scrooge dream, or was he visited by true ghosts? Either way, he woke up and understood and was changed. Not so much here

My interpretation was that everything we saw actually happened. Krampus reset everything for the real world and the bell told them all that the same "dream" everyone had last night was real.

Krampus keeps a copy of the family in the globe as a trophy. Or maybe as a tool to send them the dream again if they stray too far away from Christmas cheer.

I mean, Krampus didn't really take the whole house and family off the Earth and put it in a snow globe! If that was the case, there'd be thousands of real-life reports of houses and families just vanishing just before Christmas, along with whole neighborhoods being slaughtered.

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What Would Jesus Do For A Klondike Bar (WWJDFAKB)?

For goodness sake... Santa Claus is Comin to Town was playing as Krampus set down the snow globe. How much more obvious can it be, that those are his "windows" to keep an eye on things?