Fact or Fiction -> Stock Up: A small upgrade for blue's suite of draw spells.

Seasoned Hallowblade -> Containment Priest: Cheating creatures into play is a very powerful strategy in this cube right now that tends to be oppressive to white aggro and midrange decks. Containment Priest provides these decks a useful tool to fight back, while Seasoned Hallowblade is redundant other 2-drops and mostly outclassed by cards that can generate more incremental value.

Beza, the Bounding Spring -> Serra Paragon: Bringing Paragon back as a value engine for White. I don't think White currently needs a "catch-up" card like Beza, and mid-range decks will get more from the value Paragon provides.

Wall of Omens -> Oust: I'm favoring more removal over roadblock creatures, as I want more cards capable of dealing with top-end threats rather than preventing small beaters from getting in.

Invasion of Gobakhan -> Parallax Wave: Parallax Wave is a very powerful card that's been out of the cube for a while that I want to test again. Invasion is a good utility card for aggressive decks but is probably too slow for the cube these days.

Glimmer Lens -> Eagles of the North: Adding the full set of LoTR landcyclers, and Glimmer Lens is a marginal aggro card among many others that will sit out for now.

Whirler Rogue -> Forensic Gadgeteer: I think artifact decks will value generating clues more than thopters and the ability to make creatures unblockable, so I'm testing Gadgeteer over Rogue for now.

Confounding Riddle -> Sphinx of Forgotten Lore: I love the versatility of Confounding Riddle, but I think it's too weak overall for this cube. Sphinx is a fun new mythic that I think will be a lot of fun for controlling decks.

Lively Dirge -> Dreams of Steel and Oil: I've long wanted to add another black discard spell to help it disrupt opposing decks, and Dream has the added benefit of some targeted grave hate. I don't think reanimator needs Lively Dirge right now to function.

Phyrexian Fleshgorger -> Valgavoth, Terror Eater: Replacing one target that's generally cheated into play with a stronger one. Fleshgorger wasn't being prototyped that often, as lower to the ground black decks have a lot of strong three drops that are better.

Sorin of House Markov -> Dance of the Dead: I dislike Dance for its high complexity, but I wanted to add another reanimator spell and this is the best one that's currently not in the cube.

Glorybringer -> Trumpeting Carnosaur: Glorybringer is showing its age, and Carnosaur provides a nice top-end for red decks while also being very versatile if you don't want to put the creature into play.

Volcanic Spite -> Oliphaunt: Continuing efforts to add all of the LoTR landcyclers. Red has a lot of 2 cmc burn spells, so I don't think its needs Spite.

Explore -> Insidious Fungus: Trading off the efficiency of Explore for the versatility of Fungus.

Life from the Loam -> Generous Ent: I'll miss Life from the Loam, but the lands deck doesn't need it to be effective, so it's out to add green's LoTR landcycler.