Pluto, Determined Defender and Nani will help keep your high-value questers safe, while Evasives like Don Carnage and Wildcat let you set the pace of the game and keep your opponent on the defensive
Black has specific cards it wants to play for specific power levels and win conditions
I had somewhat just assumed this year was going to be a weak one, due to Onslaught mostly, but also forgetting how good cycling and flashback are
Sapphire/Steel can also be highly effective by anyone who knows how to wield it, but the greater element of chance that its cards create is somewhat unavoidable
This sort of mechanic greatly aids design by adding open-ended, situational upside to otherwise identical spells
You get to customize your deck to suit your personality and playstyle all while tinkering and messing around with fun, new cards