Weird at four mana. How is the Desert archetype suposed to play out? Keep lands in hand rather than playing them?

I considered 3 mana, but I was worried the ability might have been too good at that cost. If such is not the case, I would decrease mana value and p/t accordingly.

This design wasn't made primarily for the Desert archetype, but for the -1/-1 archetype (though the uncommon Desert cycles gives them overlap). The Desert addition was added as a set-relevant bonus. Either way, the general idea was that you'd have more lands in your hand than you could play in a turn, so that you could ramp.