Valley Floodcaller is going to feel like Settle the Wreckage coming down when you attack into a lot of open blue mana in these creature typal decks
On top of all that, each set has to be careful of the sets around it so that it's not stepping on the toes of what comes before or after it
The four Pioneer Challenger decks for 2022 are: Izzet Phoenix, Orzhov Humans, Gruul Stompy, and Dimir Control
This somewhat bypasses the high cost, as it will always be available to summon to the field when theres enough mana to call it
Back way when, Wizards didn't really make sure that there were ENOUGH playable limited cards in the common slots for sets (no one was playing much limited before the inception of the Pro Tour, around the release of Ice Age ), so horribly unplayable cards like Snowfall and Balduvian Shaman glutted the common slots of packs - and commons are where most of the meat of your limited cardpool comes from
This means that even if one player happens to open with the cajones with a turn-0 Leyline of Sanctity, it's not going to save them