Hey, I couldn't find "the" Merfolk Legacy forum so I figured I'd post this here. As at least one of you knows, I'm considering making a Merfolk deck at some point in the future and have been looking at a few lists out of curiosity. Wondering why no one runs Spreading Seas sideboard especially with the new lord.
Spreading Seas (or Aquitect's Will ) are not played because they are not disruptive enough in a format where most of the best decks already play Islands and can use blue mana.
Compare Blood Moon and Contamination , which aren't very good either, but they used to see play because they neutralize multiple lands, and also red and black are less popular and therefore the respective mana is less useful.
In Legacy, Blue is the best color. Let's punish blue, in Modern. And they listened!