It's already ridiculous that players are able to bite other players as frequently as they can.
If the Cooldown was once a month, as opposed to once a week, you could have had another Meta game for players to strive to achieve in game (by doing content).
Then, players wouldn't have an issue with lots of players being either a Vampire or Werewolf in end game PvP - as well as lots of the remaining players running fire / poison weapons while spamming Fighter's Guild Abilities (countering the playstyle).
Adding in Bites through the Crown Store, will just make the situation even worse..
Also, while you are working on (or thinking about) adding in a way to change your race through the Crown Store - can you make a way in game to turn your character into an Imperial?
You're really riding the line of pay to win, by allowing it to exist by buying it - but not a way to obtain it ingame..
The racial passives Imperials have, make it this way for many playstyles.