Both make sense thematically, but vampires are already scary enough in melee for my taste...

If it's swapped for St and To drain, then yes. If it's on top of their powers - I'm kinda scared.

I don't think they are that threatening at this point, they have a high toughness and an occasional drain attack but nothing too serious. The RFE makes sense.
On the other hand I usually encounter vampires at the point where I don't really care how tough they are because I can handle them with ease anyway.

No more berserking, that's way too abundant already.

If they manage to damage an already bleeding PC, they could get healed for added flavour. As this doesn't happen so often, the amount of healing could be a bit more than "slightly".

What about characters becoming vampires or werewolves when seriously damaged by them? Depending on the moon your tactic could only be more aggressive, getting damaged by the sun in the wilderness, taking more damage from silver weapons, maybe an special bite attack in both cases (like kicking), special methods to remove the curses, maybe by killing an older vampire/werewolf... So many fun possibilities! :D

I agree. In fact I've always considered stat drains to be a quite lame and unfun mechanic in its current state - so swapping it for new, much more exciting abilities is a win-win IMHO.

I don't like the idea of Berserk + Stat Drain together. It makes Vampires way more lethal for those that have problems with them, and adds little for those that can handle them already.

More interesting I think to take away stat drain, add the blood-berserk, AND make vampires way more likely to inflict bleeding (maybe armour piercing?). Making the lifedrain was dependant on bleeding would be awesome thematically, if possible.

So:

The Vampire hits you. The vampire draws blood!
[[Bleeding]]
The Vampire goes into a frenzy at the scent of blood! The Vampire hits you. The Vampire looks healed. The Vampire missed you. The Vampire hits you. The Vampire looks healed.