Thought Experiment

After watching The Professor's latest video on the Modern format, where he calls on all ten fetchlands to be banned, it got me thinking.

The fetches should be banned, he suggests, because they are design mistakes-allowing for perfect mana, breaking the color pie, and creating lag time in games where players just shuffle.

A similar argument has been made against dual lands. They are too powerful, they are design mistakes and every attempt to 'fix' them is either broken (as with the Battle for Zendikar and Oath of the Gatewatch wrecked standard, and the Ravnica lands are a force in every format they can be used in save Vintage) or terrible (Amonket and Hour of Devastation). 

Other attempts at making lands that tap for two colors, as useful as I think they are-be it from the Mirroden blocks or Shadowmoor-just don't have the same kind of power. Similarly, nobody is clamoring for more copies of Terramorphic Expanse, but we have them.  

So an interesting question for me is: Would you rather have dual lands, or fetchlands? 

Fetchlands enable a lot of decks that otherwise wouldn't exist, but those decks are generally graveyard-reliant ones. Blue would take a pretty solid hit, as the utility of Brainstorm would diminish significantly. 

Dual lands are critical for manafixing and really expanding what is possible in the realm of deckbuilding. Doomsday right now is a prime example. I've heard that deck described as "a Blue deck that can produce BBB" and that kind of thing just isn't possible without dual lands. 

But then again; is it possible without fetchlands, either? How many decks just fold up and wither without one of these two components?