A bit on the grim side, but also fun after the dying part, so here goes:
Let's take a closer look at these exciting options.
- Captain Marvel (Shazam): Plenty of powers to make it possible -- after all, hitting every single house of every single "good" Christian child in the world is a tall order. Sure, it's likely that Santa's got magical goodies that make the whole enterprise workable, and those goodies could be used by his replacement, but just in case it doesn't hurt to have the speed of Mercury. Plus, Captain Marvel is also Billy Batson, young boy, so he would have first-hand knowledge of the Christmas spirit and the joy children take in getting gifts.
- Darth Vader: "Feeeeeel the POWah ... (whooo haaaa) ... of the DARK SIDE! Lego set, I mean. And, um, the Feed Me Susie Doll. Oh screw it ... " (whoosh whoosh, light saber cutting down Christmas trees and stockings). Money, baby, pure money.
- Dr. Doom: Doom would use the power of Santa to take over the world, and if that doesn't spell "Christmas Joy" to you, nothing will. Plus the "Bad List" would be excellent fodder for Doom's Army of Doom.
- Hulk: If you liked the green-skinned Grinch, you'll LOVE green-skinned Hulk Santa!
- Superman: Like Captain Marvel, but with even more super-powers to make the job work. X-Ray vision would be an invaluable aid to the "He sees you all the time" requirement.
- Wolverine: "Why did Santa bring everyone confetti this year?"
The "serious" answer (if such a thing has any meaning with a question this stupid) would be Captain Marvel. The "fun" answer would be Wolverine, because he'd do the job but be grumpy about it. And the "best" answer is, of course, Doom.
I look forward to your answers and suggestions!