Tempo is all about what you get for you mana and how quickly you get it
The first change is to the rules, and it is the only rules change: From now on, when the archenemy attacks any player or planeswalker on the opposing team, any creature a teammate of the defending player controls may be assigned as a blocker by that creature's controller
Scion of Draco Despite costing 12 mana, Scion of Draco can be cast for effectively 2 mana, thanks to triomes and Leyline of the Guildpact
While I understand that the card was probably a bad idea for Standard and put a lot of players off, I will miss being able to have two of these decks jam huge turns against each other
Naban, Dean of Iteration Enter the battlefield (ETB) abilities have gotten a lot of support over the past few years
Then probably Batman and Robin