Let me bring back my often-repeated suggestion for SoFo:
5/4. 0|5. Accretion: Destroy target permanent, gain 0|10, and generate a black hole (upped for upped version)
And I'll make the sort of argument I made earlier.
Rainbows can already pack PC without using this card. This card needs a turn's wait to use, and it can be taken down during that turn, counterbalancing the playing speed of the card. Voodoo doll can similarly be packed for a high HP creature without attack instead of this, and black hole can similarly be packed instead of this for denial. A rainbow deck that did all three would be plagued with bad focus, counterbalancing the compactness of SoFo.
Gravity decks don't need PC as much, as they have denial, momentum, and catapult, alternatives for it. Gravity already has high HP creatures and denial, so this card is mostly useful as a card riskily packing 3 things into the same package.
Other decks come in 2 categories:
Some decks are desperate for PC, making the high cost worth it.
Other decks that could make use of the creature already can use PC, so this would be useful just for the 15 HP creature at the end.
Both of those would have to put up with a dead card in the hand.
Comments?
Ultimately, taking them out of other allows them to be more unique. Im not saying they wouldnt work in other, but they have more flexibility with it having an affinity.
No element is complete. Light doesn't have CC. Darkness doesn't have a more efficient rush creature than Gargoyle. Life doesn't have a way to get around a shield already in play. Death can't heal. Fire doesn't have a creature with more resilience than either phoenix or fire nymph. Water can't kill a creature with more than a fifth of the water quanta it has in HP. Air is helpless to denial. Earth can't do much about soft CC. Time is back to square one if the opponent catches up. Aether can't do much about shields. Gravity is easily outrushed. Entropy isn't strong without the RNG's favor.
The shards will be less unique rather than more, as they give something not given by any other means besides loads of more cards. They help complete elements.