A lot of players don't like a lot of things about Planar Chaos, but one thing most people can agree is cool is Damnation. Although it's just a simple colorshift of Wrath of God into black, the epic flavor combined with the need for this kind of mass removal in black control decks made the first card ever seen from the set one of its most popular.
However, since current mass creature destruction spells don't have the "can't be regenerated" clause for a variety of elegance and gameplay reasons, it didn't look as though Damnation had much of a chance for a new printing, until From the Vault: Annihilation, a mass-destruction-focused all-reprint product, was announced. Damnation is an extremely in-demand card in Modern, commanding a $40 price tag, and everyone is clamoring for it to be in Annihilation. Mark Rosewater even weighed in on Tumblr.
When keith-cancel asked, "I find it interesting that the card Damnation is a single word named card. I thought singled named cards for things you will want to reuse often? Yet, we have only seen damnation printed once?" Rosewater replied:
When we printed it we believed there was a decent chance we’d use it again.
The card definitely has fans in R&D, but they can't use it in a Standard-legal product. Perhaps Annihilation's developers wished to make up for the lost reprint chance.
When ununnilium asked, "Do you think there's a good chance of you reusing Damnation eventually?" he responded:
I think there’s a chance. I’m not sure I would say a good chance.
This may not look very encouraging, but the card does violate current design policies; if Mark weren't trying to be coy about a supplemental-product reprint, he'd essentially say no outright.