My go-to bog-standard format for playing cube with just two players is a large sealed pool where we each make two decks and then play each matchup for a total of four best of three games. Normally I showcase just one deck when I play such events but in this case we are getting both of the decks that I built. This is to demonstrate curve in the current era of cube. I would class these decks as below average in most senses. They are a bit thin on the synergy pieces that make these archetypes powerful nor do they have a high density of those stand alone bomb cards. There is a bit of a lack of focus and some less than ideal mana bases. This was the kind of pool where I was patching over holes and making the best out of the situation. These are the opposite sort of decks to those that I normally showcase. There is one thing both of these decks do correctly however and that is their mana curves. I managed to cobble together enough cards within two colours, that work towards roughly the same ends, while costing two or less mana, that the end results were impressive. I didn't drop a match with either deck and I thought that exemplifies the value of a low mana curve.
Most games and sports have a strategy that is used by underdogs to defeat more powerful opponents. In cube it is what I did with these decks. Essentially going as low as you can with decks posing questions. This gives opponents least time and mana with which to find their better cards. In constructed Magic a player might elect to run an aggressive deck so as to minimize choices for both players and mitigate a skill difference that way. In constructed Magic there is no difference in the power level of your pool of cards so player skill is the only thing we might look to compensate for. Going as low as possible with your curve in cube actually gives you a greater chance to outplay someone as you will greatly increase your depth of options by reducing the cost of your cards. Going as low to the ground as possible in cube can help mitigate a poor pool, it will not help much with a skill difference. Cube is not a kind environment to beginners and there are not many things you can do to mitigate a skill gap. If anything it is the opposite of going low to the ground. The easiest deck to pilot is likely a green ramp kind of a build which will have some of the highest curves in the whole meta. We were not looking for easy, we were looking to maximize our chances and so I presented a black base half Hogaak, half aristocrats deck, and an Izzet discard spells deck that are cheap and poor all at once!
Hogaak / Aristocrats
Stalactite Stalker
Concealing Curtain
Bone Shards
Bloodchief's Thirst
Stitcher's Supplier
Gravecrawler
Forsaken Miner
Carrion Feeder
Evolved Sleeper
Haywire Mite
Emperor of Bones
Orcish Bowmaster
Overlord of the Balemurk
Blood Artist
Priest of the Forgotten Gods
Satyr Wayfinder
Caustic Bronco
Tear Asunder
Deeproot Wayfinder
Grist, The Hunger Tide
Midnight Reaper
Bastion of Remembrance
Hogaak, Arisen Necropolis
16 Lands
3 Forest
Bayou
BG Tri-land
B Sac Land
Lair of the Hydra
Boseiju, Who Endures
Fell the Profane
Hagra Mauling
This Golgari list is the weaker of the two decks being split across two different synergies. While I did have Hogaak, who is by far and away the best payoff for such builds, I had little else of note coming from the bin, and was a little thin on support. The mana base is really shoddy too. This is one of the most pressing issues when going so low on curve. You can ill afford having the wrong balance of lands as you have such a high colour intensity in your spells. You undo a lot of the good your high option density can do if you are struggling to play the sequence of spells you want to. I played a bit more lands, filtering, and value than I might normally do in these kinds of deck so that I wouldn't suffer as much from the bad mana. Mostly what I am trying to say here is that you should be predominantly lead by your lands if you are looking to go low and all in on a two colour deck. My Izzet fixing was decent, the Golgari was still one of my better supported pairs but it was much in need of some assistance. Having so many lands in a deck with such a low curve and not an endless means of good ways to convert excess lands into something useful I went pretty ham on utility lands and tossed in any suitable mana sinks I had.
If you assume the MDFC are lands, and that Hogaak costs zero mana, and we always impend our Overlords, then this deck comes in under one mana average CMC and 1.625 average cost excluding the lands thanks to its curve topping out at three three drops. Yes, cards like Concealing Curtain and Evolved Sleeper are not great without further mana investment but that isn't really the point here. They are infact part of what lets you go so all in on low cost cards.
The Izzet list comes in even cheaper with a 1.54 average CMC across the nonlands with a smidge more free spells and fewer three drops. I found that I was casting Epiphay for X = 1 or 2 most commonly and so have counted that and the Eddymurk as costing 2.5 mana each. This list is generally fine. The mana base is OK and it has all the right sorts of things. It is a little muddled with some prowess stuff, some flurry things, and a selection of somewhat uncoordinated threats. It is not a very robust list but it is not found wanting in any area really. It is just a little underpowered compared to what I am looking for when I build a deck like this. While both of these decks are some degree under par in terms of power level, they are also both noticeably cheaper than what I might consider an ideal list, and that allows them to perform a little closer than you might expect.
Izzet Discard Spells
24 Spells
Mishra's Bauble
Careful Study
Faithless Looting
Lightning Bolt
Lava Dart
Ponder
Gitaxian Probe
Spell Pierce
Marauding Mako
Pteramander
Grim Lavamancer
Abrade
Fire / Ice
Electrostatic Infantry
Occult Epiphany
Cori Steel Cutter
Suspicious Stowaway
Hobgoblin, Mantled Marauder
Tersa Lightshatter
Abhorrent Occulus
Eddymurk Crab
16 Lands
4 Mountains
5 Islands
Spikefield Hazard
Hall of the Storm Giants
Ash Barrens
Volcanic Island
Shivan Reef
Thundering Falls
Spirebluff Canal
Optimal looking curves in cube naturally fluctuate up and down over time as people adapt and alter the meta. Things typically get cheaper and faster to a point then everyone starts to pack as much Arc Trail type cards as possible which really prey on low curve decks and it goes the other way for a bit. Once someone flops out an Ugin and wins with it on the spot it will start to swing the other way again! Very much like natural undulations in population levels of predator/prey relationships in the wild. This natural tidal change is brought about by the players responding and adapting and is unique to each different player base. There is also a slower and more subtle underlying trend in cube mana curves and to no ones surprise that it downward. The more cards we get access to and the more powerful they are the more it forces things down. What prompted me to write this article was noting that both my decks had curves below the average of what I would expect from modern constructed decks. I think the ideal cube curves are at that crossover point for the first time ever with modern decks and that is interesting. Probably not useful or meaningful, but at least interesting! Really all we have to say here is that three drops are the new curve toppers. Keep those curves low and if your deck still looks shit, go lower.
