last edited by Brass Man
I don't hate the idea of Mind Twist, but I wonder if you're too optimistic what the card can do without support. This deck looks very capable of winning a fight on the stack, but it might have some trouble dealing with cards that make it to the board.
3 Fatal Push being your only way to interact with the board feels very risky. For instance, if your opponent plays a turn one or two Young Pyromancer, before you have a Mana Drain wall up, even with a Fatal Push in hand you could be in real trouble. If they get even a small number of Elemental tokens in play, your deck can't really kill them, and Jace, the Mind Sculptor becomes quite bad. A single Monastery Mentor would be a real problem, or any Workshop hand where they play 2 or 3 creatures in the beginning of the game (and that's an extremely common opening for Workshops)
This doesn't mean that the deck is a dead end, but I do think you'd be rewarded for running either more removal, or more threats that match up better against the cards which are already good against your discard ... maybe Tinker+Blightsteel Colossus, maybe Tasigur, the Golden Fang, or even just planeswalkers that have more of an impact on the board ... maybe a Karn, Scion of Urza or Tezzeret, Agent of Bolas, but both of those are better with more artifacts. If you're up for splashing a color, red and white planeswalkers are particularly good at closing out the game even if your opponent has threats in play, and of course Monastery Mentor fills this role admirably.
As an aside I'll say that it's very non-traditional for a Vintage deck this controlling to run Necropotence, but the same could be said for Timetwister which is a pet card of mine in Vintage control, so I don't know that I think Necro is necessarily wrong. If you want to keep it, it may be worth running more cards to be sure you don't get locked out with no draw step ... whether that's Tendrils of Agony or more planeswalkers or Paradoxical Outcome or something else entirely, I'm not sure.