OmniStrata we were there at the event looking for you, only found you at the end where is was clear the day had taken its toll. After reading the bad beats,, I can empathize. I have a few notes after reading your report:
Round 3 Game 2 - You say he cast
Witchbane Orb, which should shut off
Liliana of the Veil's -2 & -6 ability, but you say you used this the turn after the Orb was played.
Metalworker is a mana ability, it can't be turned off with
Pithing Needle. You'd need
Phyrexian Revoker to do that.
Round 6 Game 2 - You say your opponent cast
Abrupt Decay targeting your
Mishra's Factory. That isn't a legal target, you should have been able to continue the beats into Jace's dumb face.
Beyond that a good read and some tough breaks for you. My wife was there running Pox and did even worse, facing two OmniShow decks as well as the mirror. We used to have 4x
Leyline of the Void in the side, but recently swapped them for 2x
Relic of Progenitus and
Extirpate. It offers us a better range of hate and the flexibility of not always needing to bring in 4 copies to maximize the opening hand. We're playing without library manipulation, so our deck is our deck, and putting in cards that do nothing when drawn is a really dangerous prospect. Yes our set up is weaker against DTT, sometimes Relic just isn't enough to keep them off Delve, and since you can't respond to paying a cost, it's too late once they can. But I think it makes the deck stronger as a whole, as well as giving us better game against RG Lands and OmniTell. (My wife hit Show and Tell with an Extirpate, though the opponent had anticipated this and had brought in Young Pyromancer, her Engineered Plagues were still in the side, and couldn't kill them faster than he was making them and died, but still, good play that was potentially game over against that deck) If DTT continues its rise and becomes a serious issue, then maybe we will reconsider, but for us locally, casting a wider net has more benefit than crushing just one card.