Rares and uncommons typically handle one job well, while Mythics handle several
PyroclasmPyroclasm is cheap already, why would you want to ditch a card for the privilege
Ajani Goldmane Ajani Steadfast Ajani Unyielding Ajani Vengeant Ajani, Adversary of Tyrants Ajani, Caller of the Pride Ajani, Inspiring Leader Ajani, Mentor of Heroes Ajani, Nacatl Avenger Ajani, Outland Chaperone Ajani, Sleeper Agent Ajani, Strength of the Pride Ajani, Valiant Protector Ajani, Wise Counselor Ajani, the Greathearted Aminatou, the Fateshifter Angrath, Captain of Chaos Angrath, Minotaur Pirate Angrath, the Flame-Chained Archangel Elspeth Arlinn Kord Arlinn, Embraced by the Moon Arlinn, Voice of the Pack Arlinn, the Moon's Fury Arlinn, the Pack's Hope Ashiok, Dream Render Ashiok, Nightmare Muse Ashiok, Nightmare Weaver Ashiok, Sculptor of Fears Ashiok, Wicked Manipulator B.O.B
The intentional including of some weaker, not-on-theme cards for the reprint machine, like Brilliant Plan, Kongming, "Sleeping Dragon", or newer cards that weren't on theme like Tidal Force are the only things keeping the synergy from your deck from breaking people in the face unfairly