Most of these things are at least thirty years old and require forgers to get thousands of tiny details exactly right
Ajani Unyielding Ajani, Mentor of Heroes Ajani, Sleeper Agent Ajani, Valiant Protector Anthem of Champions Aragorn and Arwen, Wed Arahbo, Roar of the World Armada Wurm Arwen, Mortal Queen Black Panther, Wakandan King Brightglass Gearhulk Byrke, Long Ear of the Law Calix, Destiny's Hand Calix, Guided by Fate Captain Sisay Captain Sisay Dr
Given the best manabases for prEDH would use OG Duals, Fetchlands, and Shocklands, not having easy access to one (or more) of them puts non-legacy players in the rough spot of relying on prEDH's limited and patchy color-fixing options which can leave new decks performing at a more clunky pace than they otherwise would be if built back in New Phyrexia
Overlord of the Balemurk would be pretty medium without an impending cost of 1B, and its this that takes it from medium to more playable
Last March of the Ents Last March of the Ents is an incredibly expensive sorcery out of LotR: Tales of Middle-earth that not only cannot be countered but also draws a ton of cards
