This is also very creative and interesting. But I think that it would be better to split this into 2 cards.
You could have one be a split card of Good Fortress/Evil Fortress, that had the power to negate all opponent's cards of the same type. That way if you choose Good Fortress it would be harder for your opponent to target, but would only negate good fortresses (which is not as bad for the game). If you choose Evil Fortress, it would be more dangerous for your opponent, but also easier for them to target. You also should ONLY get to choose when it first enters play, NOT every upkeep.
The other card could be a mutli-colored site that negates your opponent's sites as long as it was occupied. That would still be really powerful, but would give your opponent ways to deal with it (Burial, SoG, rescuing, cards that discard occupied sites, etc.). It would also be useful for site access since it would be multi-colored.
