As wonderful as it is to see the Modern metagame since Modern Horizons 2 continue to change week to week, the script it's following is rather predictable. We had the typically turbulent opening weeks of Magic as players tried anything they found interesting, and powerful new cards that found a home quickly got all the hype — in this case it was Urza's Saga.
This was followed by the establishment of the first archetypes that would set an established metagame rather than just fade away once the tricks were figured out — in this case the fair Ragavan, Nimble Pilferer and Dragon's Rage Channeler decks. These midrange decks were both powerful and flexible, which allowed them to adapt with the dynamic metagame. They were initially attacked by Mono-White Hammer (Lurrus), but were able to figure out the matchup without much struggle.
Eventually, the midrange decks started adapting to beat each other, leading to a classic arms race where the midrange decks slowed down and incorporated more card advantage to win the attrition-oriented midrange mirrors. Eventually, that arms race leads to a potential exploit by decks that focus entirely on going over the top of their opponents, most exemplified recently by the return of Mono-Green Tron.
Last weekend, we saw the next step in the evolution of the Modern metagame, and that's a return of linear decks that go underneath Mono-Green Tron and friends while having enough resilience to also capitalize on midrange decks that are still inbred to beat other midrange decks. The results show a multitude of such linear decks, and it's unclear exactly which ones will disappear quickly and which will stick around to some extent.
I've looked deeply at each deck, and based on its raw power and ability to adapt moving forward, I will decide whether I'm buying it as a future player in Modern, or sell it as a worse option that will struggle to find consistent success moving forward. Note that I'm focusing on archetypes that are currently on the rise, rather than established linear decks like Living End and Mono-White Hammer.
Buy: Boros Burn (Lurrus)
This is the most successful of the six decks I'll be covering today, and is an easy buy. With the influx of powerful cards in Modern Horizons 2, decks are better at interacting with the battlefield than ever before. And the simplest way to not play that game is to focus entirely on the life total axis.
Moreover, the most important qualities to have as a linear deck to beat big decks like Mono-Green Tron are speed and consistency, and Boros Burn (Lurrus) has that. It's not the fastest deck around, but it's fast enough to race and incredibly consistent due to shear redundancy.
There haven't been any major additions to Burn in recent years, but filling out the list with Skewer the Critics and having a significantly better mana base with Inspiring Vantage and Horizon Lands all serve to add a few percentage points across the board. And Lurrus of the Dream-Den, which to my ongoing astonishment many Burn players still haven't adopted, adds a level of insurance against mana flood that Burn desperately wants.
Burn isn't the most adaptable deck, but fortunately it's quite difficult to gameplan against it with direct hate cards because the metagame is too wide. Any deck with a combination of removal, discard/counterspells, and pressure will be at least competitive against Burn, so there isn't much incentive to go out of your way to solidify the matchup when there's so many other things to worry about. So I don't anticipate a huge uptick in Kor Firewalkers, Timely Reinforcements, and Dragon's Claws unless Burn becomes much more popular.
Lastly, I like Burn because it's a surprisingly difficult deck to play well. Despite its reputation as simple and straightforward, there's plenty of intricate lines you need to make with Burn to give yourself the best odds to win, especially when playing around various pieces of disruption your opponents can have. Whether it's holding your burn spells in the face of counterspells to set up one big turn where your opponent runs out of mana, or knowing when to Lightning Bolt an opposing creature and when to go upstairs and hope your deck serves up the rest, Burn presents a number of tricky plays and nuanced decisions to make, and the best players of the archetype will see it reflected in their win percentage.
This ability to outplay your opponent is often less prevalent in linear decks, and gives Burn a real advantage when picking between them.
Sell: Selesnya Hexproof (Lurrus)
Ever since Reid Duke took Slippery Bogle to the finals of the World Championship, Selesnya Hexproof has regularly popped up as a potential metagame choice at various points in Modern's history. It was a deck players looked to to answer the Eldrazi Menace during Eldrazi Winter, as well an answer to Dredge when it was dominating the format. But in every case, the deck has ultimately fallen short, and I don't see that changing any time soon.
The general problem that this deck has each time it looks like it might be good again is that it's just not very consistent. Even with the London Mulligan rule, having only eight hexproof creatures leads to an incredibly high fail rate. And with how much removal there is nowadays, your backup plans of Kor Spiritdancer and Dryad Arbor aren't working nearly as often. Lurrus may be the best card in all of Modern, and it certainly helps on this axis, but you can gain the powerful companion in a number of other decks.
Beyond the difficulty in consistently finding a hexproof creature, this deck also needs the right assemblage of Auras to win games. In some matchups you need to race with Ethereal Armor and All That Glitters, in others you need the resilience from Umbras, and in others you need the Rancors and Daybreak Coronets to make sure you can break through wide battlefields. Infect gets evasion from some of its threats, and Mono-White Hammer can tutor for its one Shadowspear with Urza's Saga, but Selesnya Hexproof is dependent on its deck to find the right pieces, and that just doesn't cut it in 2021.
More specifically, Selesnya Hexproof doesn't match up well against Mono-Green Tron, the number one big deck that these linear archetypes are trying to beat. Oblivion Stone, Ugin, the Spirit Dragon, and All Is Dust are all nightmares for Auras, and Karn Liberated and Wurmcoil Engine can also be quite powerful on the right battlefield. I wouldn't touch this deck until it gets some major upgrades from future sets, because right now it's a relic of a bygone era.