If you had four copies of a card in your collection that had the same name and the same artwork, it was considered a "full reprint" and would only be opened in packs if you had already collected all other cards of that rarity in that set (same as if the card was banned in Constructed play)
It's possible there's some crazy Ali Antrazistyle combo deck that can take advantage of it, which keeps it from being graded even lower, but Invasion of Arcavios looks like a Commander card to me
It is arguably the most powerful Spirit boss monster, as it can be easily summoned, and provides a strong continuous lockdown effect, providing real field presence in the opponent's turn if the player manages to have "Amano-Iwato" stay on the field
As logical and likely tempting as this may sound, be careful doing this, particularly if you have to jeopardize vital colored mana sources
[78] Other games also influenced the design at this point, with Garfield citing games like Cosmic Encounter and Strat-o-matic Baseball as games that differ each time they are played because of different sets of cards being in play