Geonigma


Target opponent may put a Plains into play, if that player does not that player sacrifices a Plains. Repeat this for Islands, Swamps, Mountains, and Forests (in that order).
This way you don't make all the choices at once. In this example, the duel lands don't really help you (they can actually hurt you if you put them into play foolishly).
I think for 4 mana though, the odds of it just being "target player sacrifices a land of each type" are fairly high. They would have had to not miss a land drop for 3 straight turns and still have lands in hand. I feel like this card is much more powerful the later the game gets. you basically want to cast it the turn immediately after they miss a land drop.
I'm not sure if this is too good but you could do...
Geonigma II


Choose an opponent, and a basic land type. That player may put a land of that type into play, if they do not, that player sacrifices a land of that type. You may pay

to repeat this, but you cannot chose a land type previously chosen for Geonigma II.
Its a little Forgotten Lore~ish. But it means it's mana cost will scale with how many lands you want to kill. But you're never going to choose land types they don't currently control (because it would just give them a free land drop).
EDIT: or you could do....
Geonigma III


Target opponent reveals the top 3 cards of thier library put all Plains revealed this way into play and the rest on the bottom that players library in any order. If that player did not reveal a plains in this way, that player sacrifices a Plains. Repeat this for Islands, Swamps, Mountains, and Forests (in that order).
This way you could REALLY help them out. At that point, Its could almost cost
