In today's column about the updated Planeswalker Points, there's an image for the 20th Anniversay of Magic. It looks like it could be new art for Akroma's Vengeance in FTV (Since it was part of the G/W Slide deck that won Worlds in Onslaught/Mirrodin Standard). I would link the art, but I'm mobile at the moment.
Nightmare has new art. While that doesn't always mean it's going to be in, we did get Mutilate with new art in last year's DotP. So, I'm going to say yes, Nightmare is in (and that makes me sad).
Missed a line, hold on
Conflux - Nicol Bolas
Worldwake - Jace
Mirrodin Besieged - Tezzeret
Dark Ascension - Sorin
Gatecrash - Gideon
So, there's that.
Looks like Theros is to Enchantments what Mirrodin is to Artifacts.
This is how I use it. It's pretty good in there in a dedicated life loss deck.