Fun Haus did what he needed to. He provided a threat and an evil plan. They based the character's appearance on the Superfriends version of the Toyman, so I'm a bit confused as to why they went to the bother of making a new character for a single episode, especially when the actual Toymaker ended up appearing. Rights issues? I don't know. Overall, Fun Haus was neither good nor bad, he was a means to an end.
That end, the plot, was a good one. Fun Haus' continual misdirection was clever, and his overall plan wasn't bad either, though the overtness of it didn't lend itself to not being thwarted. Red Tornado's quest is heartwarming and well-handled. In making the ultimate sacrifice, he got his Christmas wish. Of course, he wasn't down and out, and so his tingly-feeling didn't last.
Batman's story makes a lot of sense. It's a bit cliche to tie in the plot of a story to the night Batman's parents died, but it works in this case. Batman (who canonically hates Christmas) gets a reason to dislike Christmas that makes sense. Specifically, his guilt over his reaction to his Christmas gift indirectly leading to the deaths of his parents. The multi-part flashback sequence provides a B-plot which also provides a perspective on Batman's aversion to Christmas as well as an interesting mystery.
|Though there may be other reasons for Batman's attitude towards Christmas....|
Overall, this is quite a good episode, but with the caveat that it definitely matters what time of year you watch it. During Christmastime, the sheer Christmasiness of it is quite welcome (especially the reference to Santa Claus Conquers the Martians, for me). Other times of the year, it kind of loses its charm.
Still, it's Christmastime now. If you find yourself so inclined, I recommend this one over the next couple of days.
Merry Christmas, to one and all. Have a safe and happy holidays!