Abilities that look at the opponent's cards

BigMao

Does anyone remember Glasses of Urza? I think it would be very fun to have cards that allow us to view the opponent's hand. This would make a number of spells much better, particularly the Blue mana-draining or Black discarding ones.

Dreadalus

Finally, someone going all the way back to cards I played with, lol. Yeah, I remember, and I figured that we can slide out the opponent's hand for a reason, right? If that's never going to be a mechanic, there's no reason to have that ability at all.