What irks me about threads like this is that the argument jumps to whether or not something is "overpowered" when it's more complicated than that. I've said previously why I don't like what C3PO does to the game. The existence of counters does not automatically invalidate one's opinion about the card.
What I don't like about C3PO is that it strengthens the Falcon against what it was already strong against: 3-4 ship builds.
For example, Falcon already gave three elite interceptor builds a hard time (and rightfully so) and C3PO makes a hard counter harder. Its attack arc cannot be outmaneuvered, negating the interceptors primary advantage. The best the interceptors can do to compensate is focus fire and hope for the best, which is obviously where C3PO comes into play.
My second point about C3PO is that I think it's undercosted. For the amount of shields and hull it can save you, three points is a steal. Let's face it: that one green die will fail you most of the time. If C3PO saves you from one hit, which it likely will, it already paid for itself. Every hit it saves past that is an absolute bargain, especially against low ship number lists.
TL;DR:
Regardless of whether a counter exists, it's possible to not like a card because of what it does to the game.
I disagree.
Sure, 3 Interceptors against a Falcon is pretty tough, but it can be done. You can still block the Falcon denying it taking the evade action and guaranteeing that your ship can't be fired at. You can switch off between all your ships to spread their life out as long as possible. With blocking, 3PO only guarantees 1 evade a round. Not hard to overcome that.
I also disagree about 3PO being overcosted. You count it as having the same value as a Hull Upgrade, but it really doesn't on a 1 agility ship. A hull upgrade on a 3 agility ship is worth WAY more than on a 1 agility ship. You need to really look at it as how many extra rounds of life it grants you, not hits. Chances are, 3PO has the potential of granting you one extra round of life. So, one more chance to shoot. Hull upgrade on a 3 agility ship also has a good chance of granting you an extra round of life. So in that case, they are worth exactly the same.