Something about this list seems off to me. Maybe it's all the discard spells in it. Those seem especially bad in vintage at such a high number. I think 2 thoughtseize main and 2 board is enough. They get very bad in the late game and they aren't even great in the early game. This is not modern where you are taking away their first and ONLY play. This is vintage where if you take away a powerful line, they still have a second powerful line to take. And then you keep drawing worthless cards in the long run.
I'd rather see more impactful creatures in the list than discard cards. Unfortunately, that probably means, and as much as I love Grim Flayer, that Grim Flayer becomes unplayable in the list because you will have one less archetype in the yard.
I like manglehorn, confidant, deathrite shaman. I like flametongue Kavu or some other creature removal/creature hybrid.
Jund wins because of two for 1s. I don't see a lot of value cards in this list. Mostly 1 for 1.
You also get access to rootmaze to stop paradoxical outcome lists.
Oh yeah and Liliana of the Viel is unplayable in Vintage. It does nothing vs 90% of the field.
If you can find a way to get more ramp cards, mind twist becomes viable. I don't know if that means playing mana crypt and off color moxen or lotus petal or spirit guides. But I think the key to this deck becoming success hinges on Mind twist's inclusion and being able to cast it for 3-5 on turn 2.
Green suns zenith and dryad arbor aren't playable in vintage either. GSZ is just a bad card. You are always overpaying 1 mana for whatever creature you are trying to get. The versatility of it is punished in Vintage especially because 1) it's a spell and more cards effect spells than creatures 2) tax effects exist.
So cut the green suns, Liliana's, bad discard spells, grim flayers, garbage green sun tutor cards like dryad arbor and gaddock teeg.
Add ramp, fastbond, more wasteland effects, mind twist, and probably play the 4 of the walking crucible dude, and some number of flametongue kavu. You could even just play crucible of worlds on top of the creature copy too. I really like that idea, along with fastbond and Mind Twist.
See what I did there. I took out fair (often terrible cards) and added in a bunch of powerful ones.