I think it may be because Yuletide fandoms are so tiny that Yuletide fics kind of try to be THE exemplar of a certain aspect of that fandom, instead of being one of a thousand iterations of certain tropes/plots/whatever like the majority of fics in bigger fandoms. It's more of an, "I will carve a tiny and perfect cameo jewel that will invoke rapture and awe in all who behold it!" situation instead of an, "I'll toss a bunch of random stuff into a wok and see what happens, hahaha, somebody's bound to eat it even if it tastes kinda weird," scenario. Or something like that, I dunno, I'm probably not making much sense.

Anyway, yay remixing! :-)