DiabloFans

Okay so you want a human/mortal vampire?

I still think the name can't be used again without it being confused with Vampires in d2.

Besides that summoning overlaps the WD summoning, yes d2 had a necro AND druid but druid only came after the expansion.

Blood tree could be fun but if not made carefully it may end up just resembling skills + a life leech item.

Curses will be handled by the Witch Doctor's Voodoo and Spirit Skill trees. Mass Confusion and Horrify are already there.

Vampires are already in Diablo.

http://classic.battle.net/diablo2exp/monsters/act1-vampire.shtml

It says "undead" but it says they're spawned from hell, so that's a demon to me.

They're demons, and I highly doubt we'll see a demon class or even a non-human one.