Thanks for the article Steve. I thought fetchlands (the Onslaught and Zendikar block ones we're all familiar with, and the first versions (that ETBT, from Mirage block I think?) that people may not know about) were worth mentioning as an aside. While they don't produce mana themselves they're used for mana-fixing in the same way duals are. It leads to variations on future design space, instead of the duals you proposed at the end:
Choose-your-own-Tundra
Land
When ~this~ comes into play, choose blue or white.
Tap: Add one mana of the chosen color to your mana pool.
You could recreate a similar effect with a modified fetchland:
Find-half-a-Tundra
Land
When ~this~ enters the battlefield, choose island or plains, then sacrifice ~this~ and search your library for a basic land with the chosen type and put it onto the battlefield, then shuffle your library.
Such a fetch would offer a budget alternative to ONS/ZEN fetchlands that are better in one respect, they don't cost a life, while offering a drawback: the inability to save the shuffle effect for a later Brainstorm etc, and the inability to save the ability activation for a *safe* time when the opponent can't stifle. Also you wouldn't be able to fetch a dual land with the 'basic' wording above, but that could potentially be dropped, though another drawback may need to be added.
I think if the goal is to lower the barrier to entry for eternal formats then we're more likely to get a worthwhile competitor for the fetchlands than the ABUR duals.
All in all, thanks for the cool read. I would love to see a super-cycle of Tainted lands, i.e. four Blessed Lands that require a Plains to become duals, etc.
