I love the instant flavour in the description.

“Even more efficient”, very Phyrexian.

I have been trying to come up with a sold Yawgmoth build and I can not fault this list, except MAYBE Nyx Lotus could be added in if you like it.

+1

Thanks for the comment and upvote, and best of luck with your own Yawgmoth build Poly_raptor.

When it comes to Nyx Lotus, I have to be honest and say that not only do I not think it's good enough for this deck, I'm personally of the view that it's just a bad card in general, especially when Nykthos, Shrine to Nyx already exists. To explain in more constructive terms, there are several reasons Lotus probably doesn't work in this build:

4 mana for a conditional mana rock is much too slow for the pace of this deck, as I can potentially win as early as turn 4 (the average from my testing via goldfishing is turn 6 and a god-hand makes turn 3 possible). With that in mind, Lotus is probably a dead draw a lot of the time in this build.

Secondly, it enters tapped, which makes it even less useful as there's a good chance it'll be removed before I ever get to use it. In some ways, having a removal magnet like that isn't the worst thing, but it's not ideal. More pertinently, even if I do untap with it, its utility is entirely dependent on my board state, meaning I could have paid 4 mana and waited a turn to only gain 2 mana.

The third reason is one specific to this build, namely the fact that Lotus costs 4 mana and hence competes with Yawgmoth and two of the four Undying creatures on curve. In a deck with just 33 lands in it (and potentially 32 after a series of minor tweaks I'm pondering), this is less than ideal: I ideally want to be casting Yawgmoth on curve as much as possible to get the deck's engine going. As such, I can't afford there to be too much competition on curve with Yawgmoth, especially in the form of ramp pieces (which will be utterly useless if I can't hit 4 mana to cast them to begin with). That's also why this deck doesn't run Solemn Simulacrum.

One little piece of advice for your own Yawgmoth build that I can give from experience: Proliferate synergies are a trap and aren't really worth it outside of Infect. You do need to have stuff like Blast Zone to deal with graveyard hate too, but it's not worth leaning on that ability of Yawgmoth's too much.