Mana Drain these days has been relegated to a one or two of in the archetypal "Big Blue" decks (your Tinker decks and decks of that nature). While it's sad to see a hard counterspell leave the format and without Mana Drain having only Force of Will as an answer to everything Vintage has become a different place over the last 3 or 4 years. Mental Misstep is almost an auto include in any blue deck with Force of Wills sans Outcome based decks and even in the Grixis Tinker decks you generally have one mana open rather than two making spells like Flusterstorm and Spell Pierce better options. I personally have been playing some extra removal spells in my Pyromancer lists with Lightning Bolts and Swords to Plowshares joining the artifact hate removal spells like Wear//Tear and Fragmentize.
Misstep being amazing when it's good and a blue card for Force of Will has been good enough for me but I'm also very wary to play too many cards that feel dead in various matchups. Because Misstep is such a narrow card, and yes I do understand the high number of one drops in the format, I often use my Missteps fairly aggressively as to get value out of them. While I feel Mana Drain is still a fine 1 or 2 of in Tinker decks with both a lot of artifact mana and good outlets for both the artifact mana and the mana associated with Mana Drain, I have been shying away from it as of late and moving myself towards more Flusterstorms and a stronger proactive gameplan with the games revolving more around me throwing haymakes such as Jace, Yawg Will, and Tinker with Flusterstorm as both an excellent protection spell as well as being solid against spells like Ancestral, various cantrips and card draw, as well as Paradoxical Outcome.
Misstep being amazing when it's good and a blue card for Force of Will has been good enough for me but I'm also very wary to play too many cards that feel dead in various matchups. Because Misstep is such a narrow card, and yes I do understand the high number of one drops in the format, I often use my Missteps fairly aggressively as to get value out of them. While I feel Mana Drain is still a fine 1 or 2 of in Tinker decks with both a lot of artifact mana and good outlets for both the artifact mana and the mana associated with Mana Drain, I have been shying away from it as of late and moving myself towards more Flusterstorms and a stronger proactive gameplan with the games revolving more around me throwing haymakes such as Jace, Yawg Will, and Tinker with Flusterstorm as both an excellent protection spell as well as being solid against spells like Ancestral, various cantrips and card draw, as well as Paradoxical Outcome.