So what is the purpose for this "new cycle of
lands" supposed to be? To give commander decks another land or two to add but which will not be any better than current cycles in other formats? To be a new bomb in legacy formats and drive the price of fetch
lands even higher by giving them even better targets?
You want dual
lands that include the basic land types? How about this for the template?
[land name]
Land -
Plains Forest[land name enters play tapped]; if [land name] is the second land to enter play this turn untap it. (similar to
Fabled Passage)
Now would that see play? If you've got fetch
lands could there be a better target? A format without ways to play/put into play that second land it might be
dead weight but if running a format where you could play a land and then use that land to find this people would be all over it.
A second "cycle" could be the "not quite the original dual
lands"
Not-Underground Sea
Land -
Swamp IslandWhen Not-Underground Sea enters play lose 1 life.
I'm thinking that's a close as you could get to the original dual
lands. It'll always hurt to bring them in instead of just some of the time as with the shocklands but they'd give you the types you want faster and with less early pain even if they may not be quite as good late. A cycle of
lands like this should be printed as Common because you know everyone will want full playsets to use in every format although even at common I believe they'd quickly
jump to more than $1 and could quickly come close to other dual
lands which may see a drop in demand.