It'snot really overpowered since u need to need to go through the process of being both a vampire and a werewolf to use it and there are different kind of presets that u choose from in-game (both weakness and powers-powers only-transformations only etc),
also one of the good things is that it's not a forced kind of mod, like how the add items in 4.4 is there(and that's definitely overpowered) and u can just drop or ignore it = )