Time Walk is as powerful as it is simple - you play two mana to take a whole second turn after the one you're currently doing
Ezuri's Predation serves as a board wipe for any of your opponents creatures under 4 toughness and has the added benefit of possibly leaving you with some creature tokens
On turn one this is useless and that is really when you want to hit targetted discard against most lists
You'll need a deck that can make use of your milled cards to get the full value out of Palantr of Orthanc (above all early on, when your opponent is unlikely to let you draw), but once the counters start piling up the Palantrs often a free card per turn
For less flexibility (Ancient Grudge, Ray of Revelation, Divine Offering) you tend to get card advantage or some other upside
711.2a In every zone other than the battlefield, and also on the battlefield with its front face up, a double-faced card has only the characteristics of its front face