The multiple formats all star card Expressive Iteration takes up the number 1 spot of our multicolor list. Although I put it on 3 in my personal list for Modern, this specific decision was definitely harder than for the rest and I can see how in a vacuum Expressive Iteration can be the true winner.
In general Expressive Iteration is a great card. For 2 mana you draw one card and play one out of the top 3 cards. Being 2 mana only makes it an incredible turn 3 play, even turn 2 if you count in 0 mana cards like Mishra’s Bauble.
With Expressive Iteration being in so many decks and reaching all 4 copies even in a format like Vintage, I hear a lot of players saying the card is too good in both Modern and Legacy, comparing it essentially to Treasure Cruise and Dig Through Time, which both formats have seen and banned.
Since I already played with all of the mentioned cards, I absolutely disagree with this sentiment.
Unlike previously mentioned Treasure Cruise and DTT, Expressive Iteration actually requires more specific deck building and has in general a much lower power level in a Fetch Land format. Being in Izzet colors makes it already more color restrictive, so unless you’re playing exactly UR Murktide, you’re looking at least into a 3 color shell to make Expressive Iteration work.
Second point is, the card draws only 1 card and forces you to make a play out of the remaining 2 cards. The exiled card of Expressive Iteration may often be a non-optimal play and requires either a very low curve to fully capitalize on it exactly like Grixis Shadow or UR Murktide, or an ongoing finding of additional land drops.
I know that being especially in Izzet, an aggressive color combination with low to the curve threats, the card opened up the archetype to become extremely good especially since the printings of absurd Modern Horizons 2 creatures like Ragavan, DRC and Murktide Regent. Still, I believe that Expressive Iteration actually has deck building restrictions to it, being almost non-abusable in combo decks and holds up a much lower ceiling in Control decks. That argumentation applies even more to Legacy than Modern since you clearly see Expressive Iteration being extraordinary in Delver, good in Control and non-existing in absurdly strong combo decks like Storm, Doomsday or Sneak & Show.
For Modern, Expressive Iteration is definitely the go-to card advantage and grind machine after the banning of Lurrus of the Dream-Den and we definitely continue to see it on top of the meta share and win percentages. But nowhere is the card close to Treasure Cruise or Dig Through Time and lines up way more in the overall power level of both Legacy and Modern.