I used to use it a long while back when I could guestimate the numbers who knew about it to be countable on one hand, then as mist things do in CF, someone tells one secure friend who wont tell everyone but instead tells a.n.other secure friend and so on.

We now come to the now and everyone and their Granny knows about it and uses it with great regularity. Now ignoring the fact that so many paladins partake of the Quaggoth, which to my mind is, for a paladin, completely wrong and almost as bad as a stench bull orgy, you have shifter forms who's main attribute may be the ability to poison a victim. A lot of these forms are a bit humbled by the overuse of the Quaggoth's vigor and so I would propose the following review of it:

1) Reduce the duration because at the moment it is too long.
2) Imms smack paladins who would drink the blood of a creature, or help another do the same, to act like a vampire would for the gains they get!
3) Increase the risk by creating a one in 5 chance that your body cannot take the vigor of the blood and you are insta-killed.

I think 3 is the best idea as it is not quite the same as eating a black pudding supper!