They're powerful in that they form an engine that can grease the wheels of a life gain deck, but not so overwhelming that either of them are too likely to see a single target removal spell come their way
Keep in mind that the commander tax only applies when casting it from your command zone
I mostly talk about Blue-Eyes because I used to play a Blue-Eyes deck, it was lots of fun and eventually was one of the best decks in my small meta (I played until Paladin of Blue Eyes was new)
For the king, who always had the possibility of an accident if he couldn't pull the stage, it's a very welcome novelty, and it looks like he'll be able to build it soon
If this card is Fusion Summoned: You can send 1 Beast, Fiend, or Illusion monster from your Deck to the GY

Worldwake Card Gallery White Admonition Angel Apex Hawks Archon of Redemption Battle Hurda Fledgling Griffin Guardian Zendikon Hada Freeblade Iona's Judgment Join the Ranks Kitesail Apprentice Kor Firewalker Lightkeeper of Emeria Loam Lion Marsh Threader Marshal's Anthem Perimeter Captain Refraction Trap Rest for the Weary Ruin Ghost Stoneforge Mystic Talus Paladin Terra Eternal Veteran's Reflexes Blue Aether Tradewinds Calcite Snapper Dispel Enclave Elite Goliath Sphinx Halimar Excavator Horizon Drake Jace, the Mind Sculptor Jwari Shapeshifter Mysteries of the Deep Permafrost Trap Quest for Ula's Temple Sejiri Merfolk Selective Memory Spell Contortion Surrakar Banisher Thada Adel, Acquisitor Tideforce Elemental Treasure Hunt Twitch Vapor Snare Voyager Drake Wind Zendikon Black Abyssal Persecutor Agadeem Occultist Anowon, the Ruin Sage Bloodhusk Ritualist Bojuka Brigand Brink of Disaster Butcher of Malakir Caustic Crawler Corrupted Zendikon Dead Reckoning Death's Shadow Jagwasp Swarm Kalastria Highborn Mire's Toll Nemesis Trap Pulse Tracker Quag Vampires Quest for the Nihil Stone Ruthless Cullblade Scrib Nibblers Shoreline Salvager Smother Tomb Hex Urge to Feed Red Akoum Battlesinger Bazaar Trader Bull Rush Chain Reaction Claws of Valakut Comet Storm Cosi's Ravager Crusher Zendikon Cunning Sparkmage Deathforge Shaman Dragonmaster Outcast Goblin Roughrider Grotag Thrasher Kazuul, Tyrant of the Cliffs Mordant Dragon Quest for the Goblin Lord Ricochet Trap Roiling Terrain Rumbling Aftershocks Searing Blaze Skitter of Lizards Slavering Nulls Stone Idol Trap Tuktuk Scrapper Green Arbor Elf Avenger of Zendikar Bestial Menace Canopy Cover Explore Feral Contest Gnarlid Pack Grappler Spider Graypelt Hunter Groundswell Harabaz Druid Joraga Warcaller Leatherback Baloth Nature's Claim Omnath, Locus of Mana Quest for Renewal Slingbow Trap Snapping Creeper Strength of the Tajuru Summit Apes Terastodon Vastwood Animist Vastwood Zendikon Wolfbriar Elemental Multicolor Colorless Amulet of Vigor Basilisk Collar Everflowing Chalice Hammer of Ruin Hedron Rover Kitesail Lodestone Golem Pilgrim's Eye Razor Boomerang Seer's Sundial Walking Atlas Lands Bojuka Bog Celestial Colonnade Creeping Tar Pit Dread Statuary Eye of Ugin Halimar Depths Khalni Garden Lavaclaw Reaches Quicksand Raging Ravine Sejiri Steppe Smoldering Spires Stirring Wildwood Tectonic Edge Notable Cards The Cycle of Manlands Rare dual lands usually see Constructed play, and these ones can turn themselves into creatures
