I don't think you need to fill your opponent's cards with rares from your deck to counter the -1 facilities. In my oppinion you just helped him win the game, so unless you make this card 0-cost, I don't think it would be used by anyone. Personally, I would gladly give away my facilities to fill my hand with rares, even if they weren't from my deck :P
At any case, I feel this card does not match the concept of its name. The trojan horse was used to break inside Troy's wall. My suggestion is to make this card damage tower and turn it into something like Demolition Troops in order to also achieve -1 facilities but the condition to do so would be to affect enemy's tower. I.e.:
Cost: 10B/10G/10R
Rarity: Rare
Effect:
Enemy Tower -10
If enemy tower < 30
Then enemy facilities -1
This is just a suggestion, you don't have to change your concept, after all it's YOUR concept and you've already given a lot of good ones :)