"...fans can expect to see some of their favorite characters in the 99 of each deck..." Last but not least, Commander might be all about your leader, but RPGs are often about your party as a whole, and WOTC wont leave the supporting casts of these games hanging
otherwise youll be unstoppable
Reidane's Shield is valuable to locking down damage and countering targeting effects from everything from Shriekmaw to Swords to Plowshares to Oko, Thief of Crowns unless they spend a mana tithe

Rainbow Ramos | Commander | Stephen Johnson Commander (1) 1 Ramos, Dragon Engine Creatures (28) 1 Archelos, Lagoon Mystic 1 Birds of Paradise 1 Child of Alara 1 Chromanticore 1 Deathrite Shaman 1 Dryad of the Ilysian Grove 1 Enigma Sphinx 1 Enlisted Wurm 1 Etherium-Horn Sorcerer 1 Fallaji Wayfarer 1 Gadwick, the Wizened 1 Garth One-Eye 1 Jodah, the Unifier 1 Maelstrom Archangel 1 Maelstrom Wanderer 1 O-Kagachi, Vengeful Kami 1 Pir, Imaginative Rascal 1 Primeval Spawn 1 Seedborn Muse 1 Sphinx of the Guildpact 1 Sylvan Caryatid 1 The Ur-Dragon 1 Tiamat 1 Toothy, Imaginary Friend 1 Transguild Courier 1 Two-Headed Hellkite 1 Utopia Tree 1 Winding Constrictor Instants (11) 1 Arcane Denial 1 Assassin's Trophy 1 Boros Charm 1 Crackling Doom 1 Cyclonic Rift 1 Fate Transfer 1 Manamorphose 1 Sphinx's Revelation 1 Stroke of Genius 1 Swan Song 1 Unite the Coalition Sorceries (11) 1 Cultivate 1 Farseek 1 In Garruk's Wake 1 Ingenious Mastery 1 Iridian Maelstrom 1 Kodama's Reach 1 Last Stand 1 Mind Spring 1 Rampant Growth 1 Safewright Quest 1 Torment of Hailfire Enchantments (3) 1 Leyline of Anticipation 1 Maelstrom Nexus 1 The Kami War Artifacts (9) 1 Amulet of Vigor 1 Chromatic Lantern 1 Fieldmist Borderpost 1 Firewild Borderpost 1 Mistvein Borderpost 1 Thought Vessel 1 Vedalken Orrery 1 Veinfire Borderpost 1 Wildfield Borderpost Lands (37) 3 Forest 3 Island 3 Mountain 3 Plains 3 Swamp 1 Arcane Sanctum 1 Command Tower 1 Contaminated Aquifer 1 Crumbling Necropolis 1 Frontier Bivouac 1 Geothermal Bog 1 Haunted Mire 1 Idyllic Beachfront 1 Jungle Shrine 1 Molten Tributary 1 Mystic Monastery 1 Nomad Outpost 1 Opulent Palace 1 Radiant Grove 1 Reliquary Tower 1 Sacred Peaks 1 Sandsteppe Citadel 1 Savage Lands 1 Seaside Citadel 1 Sunlit Marsh 1 Tangled Islet 1 Wooded Ridgeline If you wanted to tune this list up, the place to start would be the mana base

This was pretty much a curve-filler in Limited, although there are some Defender themed decks that can always use the ability to attack every now and then that wont mind another option
No, they're redundant Multiple instances provide no additional benefit Example Convoke Cards Here are three cards that showcase convoke and what it enables