[card]Jace, Architect of Thought[/card], is an example of a walker you need to take care of as soon as possible (unless their life total says otherwise)
But the more mana you have to spare, and the more proactive youre poised to be (theres Quadrant Theory again!) the more efficient and rewarding this card becomes
Much of this deck is focused on the Historic characteristic, which includes artifacts, legendary cards, and Sagas
White and green are a little bit defensively focused and offer too little in the way of useful extra utility
Rad counters are not great if they are on you as a player, but lots of your Mutant creatures get powered up by rad counters, such as Mirelurk Queen and Screeching Scorchbeast
That makes it amazing in green-heavy builds full of legendary creatures and legendary enchantments