@13nova I disagree with this argument because, Thoughtseize is a very playable card against most blue decks but it is currently unplayable. And, Creature decks will increase with decks like Goblins, Merfolk and other Fish variants that will make Flusterstorm and Misdirection harder to play. Finally, Stifle used to be a card in Vintage. If Mental Misstep was gone, I'm sure a 1 blue land destruction spell will see play again.
I'm not sure I follow. Merfolk plays 4 Cursecatcher and 1 Ancestral Recall as their only 1-drops -
and then 4 Mental Misstep. How does Mental Misstep make Merfolk bad? If anything, Mental Misstep makes the deck better. That said, it's probably not a very good deck, but I don't get your logic on the matter.
And, I would add, I believe that to be the case for all Fish/Hatebear decks. Mental Misstep makes those decks better, not worse: 1) Because the Fish/Hatebear decks don't play many 1-drops themselves, and 2) because these decks benefit from "free"/turn 1 answers to broken stuff and cantrips as well as protection against the most commonly played removal.