The con is that six wildcards is a pretty small number, plus it takes a long time to fill the vault unless you buy packs like crazy
It made it difficult for decks that wanted to specifically combat mono-red to attack it appropriately, since Nemesis would roadblock actual combat, or even lifegain strategies that should be good against it
Past in Flames is a staple in both Modern and Legacy, Cabal Therapy is a Legacy all-star, Conflagrate has finished many a game for Modern Dredge, Ancient Grudge is a sideboard staple, and the list goes on, including Lingering Souls, Roar of the Wurm, Dread Return, Unburial Rites, Desperate Ravings, Deep Analysis, and Faithless Looting
Only 15 of your 99 cards can be uncommon
Crystal Barricade Crystal Barricade is a nice defense against red aggro/burn decks
The black chocobos are only printed in Japanese to honor the Final Fantasy 7 Creative Director Tetsuya Nomura