A 4/4 creature for 5 is a reasonable rate as well, though as with most of blacks best mana doublers, being a creature is a pretty significant drawback with the amount of spot removal and board wipes flying around

CATEGORY CARDSDECKS STARTER DECK -YELLOW Eustass"Captain"Kid- [ST-36] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -RED/BLACK Sabo- [ST-35] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -PURPLE Charlotte Katakuri- [ST-34] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -BLUE Kuzan- [ST-33] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -GREEN Roronoa Zoro- [ST-32] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -RED Monkey.D.Luffy- [ST-31] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK EX -Luffy & Ace- [ST-30] Release Date MSRPUSD $19.99 CARDSDECKS STARTER DECK -Egghead- [ST-29] Release Date MSRPUSD $16.99 DECKS Learn Together Deck Set Release Date MSRPUSD $39.99 CARDSDECKS STARTER DECK -Ace & Newgate- [ST-22] Release Date MSRPUSD $16.99 CARDSDECKS STARTER DECK -GREEN/YELLOW Yamato- [ST-28] Release Date MSRPUSD $11.99 CARDSDECKS STARTER DECK -BLACK Marshall.D.Teach- [ST-27] Release Date MSRPUSD $11.99

As an alternative win condition, with all the ramp and the white spells I would include for interaction and enchantments, I would also play Serra Angels
The article interviewed players' parents who believe that the game, similar to sports, teaches children how to more gracefully win and lose
A well-built Yellow deck fires a Trigger nearly every time the opponent swings, which means they're building your engine for you