Opinions After Testing
1. I don't really care that I can't see the opponents cards. If I have a control method it likely also controls Cloak. Ie RoF, pulvy, Deflag etc.
2. 2 turns is to little. I'd Rather draw another creature or key card than have cloak.
3. Its effect being Yin in nature makes unable to win games, control games and if your opponent is not using a control method of a singular nature then the card is dead.
Suggestions
1. Make it a card like Flood and require upkeep.
OR
2. Make it Immune to Targeting and the Area effects that destroy it
OR
3. Increase its turns in play to 4
OR
4. Change the effect altogether to a permanent that forces Opponents targets to be chosen randomly.