Dinosaurs on a Spaceship was just too good, and a part of every winning deck. It's way too un-interactable. I don't love adding Monarch to the cube, but I've got to admit it is interesting, sometimes getting that last card first matters, and it also interacts well with the tomb trawler/reito lantern type effects.

Winds of Abandon wasn't too good in the first mode, but creating non-games isn't super fun. Mizzium Mortars does more or less the same thing, but much less oppressively, and is much harder to splash for the 6 mana mode.

Burst Lightning is a very boring card, The Kami War is a very fun one. The 5 color deck seemed to be one people loved, and this is a very clear signpost that it's something you should be trying out. It is obviously very good, but it is slow, can be interacted with, and a 6 mana WUBRG spell winning the game if unanswered for 2-3 turns in this format is probably fine.