There are a couple things i think if added could make this mod better.
1. There should be bosses on each side. Such as the "Vampire Overlord" and the "Master Vampire Hunter." Those aren't the best names but it's just an example. The vampire boss could be found in some underground vampire sanctuary. The hunter could be found in a village style mansion guarded by other hunters.
2. There should be three ability paths that a vampire can choose from, Bats, Necromancy and Enhanced abilities.
With Bats you would have the ability to transform into a bat, have bats that swarm around you and attack your enemies such as the wolf does. For Necromancy you should be able to revive and summon zombies and skeletons and be able to zombify certain mobs. You should have the ability to control weather so you cannot burn in the sunlight. For Enhanced Abilities you should have the ability to teleport, go invisible, have special vision and increased stats.
3. Villager mobs attacks. Once you reach a certain level and aim to kill the boss there will be groups of villagers following you around to try to kill you.
Making it harder to reach the boss.