It's not necessarily a problem, but it might be better as menace, or vigilance if you want a defensive ability
Its a free sacrifice outlet in decks like aristocrats, and it can proliferate, draw a bunch of cards, and remove small creatures all by itself
Unlike Tibalt, Zariel doesnt lose loyalty to create the tokens
Cards that make the Raid Boss put cards into their hand are drawn and played immediately, The Raid Boss Pokmons Attack Energy costs are Colorless, and Energy cards are discarded from the Raid Pokmon to pay the Attack Energy cost
This is why CGC is popular for errors because they will holder anything
But more important was its ability to give any Instant or Sorcery in the caster's graveyard Flashback when it entered the battlefield