IMHO, sleeping carp should not be in the game at all.
Total immunity to ranged attacks is quite simply too strong. Most attacks in the game, certainly most of the higher-end ones, are ranged. It might as well be 'total immunity to a majority of all attacks in the game'. That's too strong.
It is ridiculous. You can't parry a bullet. Even if you were fast enough to parry or dodge one bullet, there comes a point with enough bullets where it is physically impossible to dodge no matter how fast you are. This is even sillier in the case of lasers. How are you going to deflect a laser with your bare hands? It is impossible. It reaches new heights of absurdity when you talk about things like missiles, or x-ray lasers. How exactly are you going to parry an x-ray laser which is totally unaffected by solid matter, and will pass right through your hands even if you were magically fast enough to even catch it?
It is cheesy as hell. The voice quips you do when you're using carp sound like they came out of a terrible and slightly racist kung fu movie.
That said, I realize some people might like sleeping carp.
If sleeping carp has to remain in the game:
It should not be possible to use carp as a vampire. The combination is too strong. It forces everyone else to engage the vamp in melee range, where they are strongest, it negates the vamp's main weakness (ranged weapons), and its 'tradeoff' (inability to use ranged weapons) is irrelevant to vamps as they don't need ranged weapons anyway.
It should not confer 100% invincibility to ranged weapons. Even 90% is probably too much. At most, it could give you total immunity to a narrow class of ranged attacks, like tasers. Or it could give you 75% immunity to all ranged attacks. Or it could give you the ability to dodge 1 projectile per second, but NOT more then that. Or it could only function against attacks from more than 3 tiles away. There should be *some* limit such that a full squadron of guys shooting you at point-blank range with assault weapons CAN kill you. Otherwise it just produces insane results like a full squad of ERT emptying their guns at one guy, three tiles away, and missing every single shot. That's just flat-out impossible, overpowered, and it breaks suspension of disbelief.