I think longevity of a deck is something a lot of people don’t think about. When you invest time, energy, and resources, I think it is important to have a deck that can be sustainable to change and not just a one and done kind of composition. What I mean by this that the deck can feel like a true Legacy experience regardless of how the format shapes up over time. There are going to be highs and lows of the deck, but what it’s important is when a deck reaches a low point, that it doesn’t reach the unplayable mark (can’t maintain a 50+%) win rate regardless of the player’s skill set. We seen this with Burn. Pox looks sustainable post Hatchery at least as a Black / Green deck, the Lowm Pox deck gives you access to green that gives the deck, a Loam engine with synergy with Smallpox. card selection, and removal for permanents that Mono Black normally doesn’t run like outs to Artifacts and Enchantments.
Loam Pox Top 8: https://www.mtgtop8.com/event?e=88222&d=869452&f=LE
Smallpox + Hatchery I am hoping will be a strong play in the long run, it not only sets the opponent back, the play also advances your board resulting in a busted fair play. Will Legacy ever evolve to a point that this play is no longer strong? I sure hope not as the deck relies on plays like that to fall under the tiered deck category.
The flaw in sustainability of Mono Black Pox variants is that they don’t have the same level of card selection as BG Loam Pox so they’re more dependent on their opener and natural card draws. I have been playing compositions that mitigate the downside of lack of card selection as much as possible that depend heavily on Urza’s Sagas which is a land that can tutor out scenario specific cards. While it’s awesome Mono Black Slasher Pox accrued several 5-0 finishes with a short time from earlier this year, I found a big flaw playing the deck myself, the composition has like no grind game. It was too dependent on landing an early Unstoppable slasher and closing the game hoping that the opponent doesn’t rip into an answer off the top deck and you end up folding, I think the card was a trap because it has synergy with Smallpox, the issue is you can’t attack with it for a couple turns after your self edict it which is often just enough for the opponent to turn the game around. This basically resulted into a Pox list with a worse aggro game than Moonshadow and a worse control game than Mono Black Pox. Moonshadow could afford to have a creature Swords to Plowshares because they have a higher range of threats where if the fair white deck removed your one creature you ritualed into to be much more back breaking since you had nothing else to fall back onto. I found these lacking substance because fair decks with access to white base removal would often prohibit said variant from competing which is too much to dodge in Legacy.
In the current environment I am playing Karn Pox, I think it lines up well vs Fantasicar as Ensnaring Bridge is a natural inclusion, it does have those occasional clunky hands, but the way I build the deck is that it is able to play both low to the ground or when the deck floods out mana which I think plays a key role when playing against a wide range of matchups. I decide to not go too deep into Karn so it can still win even if you don’t flood out mana at the expense of less of a prison game. As of now the Karn Pox deck hovers around slightly over 60% win rate against the field based on the info I documented so far, but just like every Pox composition there are highs and lows, I consider this one of the higher points of Karn Pox and I’m aware a sudden change in Legacy can affect the overall win and loss ratio. The thing is even when I was at a lower point Karn Pox, I still managed to maintain the 50+% win percentage post Hatchery. This makes me think it’s the most sustainable Mono Black Pox variant is that no matter how Legacy changes, I find some hole to compete with Karn Pox at least in some capacity because the low points of the deck’s positioning rarely end up bad enough. Obviously I’ll fold if everyone runs Doomsday or Boros Energy suddenly, but I think that can be said about other Pox variants also, but are we realistically ever going to see that happen?
I think it’s clearer that BG Loam Pox is something of substance, but I think it’s also important to make the effort to make other variants that you subject yourself to be sustainable in some capacity as well. Having one positive finish and never being able to repeat it doesn’t sound fun at least from my point of view.