The power and toughness drop is likely of less value than taking away all abilitiesespecially those on problematic (and perhaps indestructible) commanders
The Battlemages were simpler, as they were "virtual vanillas," meaning they had effects when you played them but were just 2/2 creatures for the remaining turns, so they went into Planeshift
Deathrite Shaman is great when the game goes long, but if a Modern game goes long, it's usually because Teferi, Hero of Dominaria or Jace, the Mind Sculptor is drawing tons of cards, or Elementals are playing through their deck, play patterns that Deathrite Shaman can't keep up with
While theres plenty to love with Obsidian Flames, I do think it suffers slightly from being released in between the Scarlet & Violet base set and Pokemon 151 expansion two mega-hyped sets that leave this one feeling a little less exciting by comparison
Liliana's Standard Bearer, Midnight Reaper, Knights of the Black Rose, Locthwain Lancer, Elenda and Azor, Pull from Tomorrow, Painful Truths, Read the Bones, Distant Melody, Path of the Enigma, Conjurer's Mantle, Vanquisher's Banner, Chivalric Alliance 13 card draw
If you have a full graveyard, this demon does a powerful Living Death impression, on top of being a 6/6 flier