Expanded Vista
Land
Reveal your hand: If your hand contains no land cards besides Expanded Vista, you may put Expanded Vista onto the battlefield. Play this ability only if Expanding Vista is in your hand, and as a sorcery.
Tap: Add

to your mana pool.
One of the big challenges in designing any kind of mana acceleration is that multiples can lead to degeneracy very quickly. This card combats that in a number of ways. For one, consistently activating the ability during an early turn of the game places constraints on deck design. Second, a hand with multiples of this does not accelerate you any faster than a hand with just one of these. Next, the cost of revealing your hand provides a strong disincentive to use this in combo decks that must fight counterspells, or even in control decks that rely on representing counterspells. Fourth, I'd think that if you manage to use the acceleration ability, you're probably going to miss your next land drop, and that helps to limit how abusable this card is. Finally, producing only colorless mana makes it harder to abuse the extra mana produced by the card.
Despite these limitations, the card isn't completely lacking in functionality in later stages of the game. All in all, I think it manages to look exciting without actually being very good, which is a fine place for a card to be.
Suggestions on making the wording simpler without substantially altering the functionality would be greatly appreciated.
Current Wording:
Expanded Vista
Land
Reveal your hand: If your hand contains no land cards besides Expanding Vista, you may put Expanding Vista onto the battlefield. Play this ability only if Expanding Vista is in your hand, and as a sorcery.
Tap: Add
to your mana pool.