1. The essence of the topic is simple. In PVP, the amount of stamina assemblies now dominates, the physical damage is slightly higher than the magic one, as the magic one is usually a distance and in this I see compensation. Its ok.
2. The magician is usually very fragile and often has to run in stealth mode. The first stage of vampirism allows you to do this more comfortably, but at the same time, sudden appearance is not particularly scary for the stamina. After all, stamina is stronger.
3. A large number of stamina builds use Downbreaker (Fighters Guild), a very cheap and powerful ultimate, however, thanks to the passive skill against vampires, this ultimate hits 20% more painfully, allowing you to simply make 13-14k damage to the body with 25k res and 3000 crit resist.
I think this is not fair, since magic can be equal in damage to stamina only in light armor. And when running as a werewolf, this increase in damage is just ridiculous, since there are more resists and health. Again, plus for stamina.