If the vampires can't suck, they suck.
Really.
The best thing about vampires/vamp dagger is that it heals you while dealing damage, essentially neutralising the incoming damage. Take an example:
You have 2 Vampires (upped),
You opponent as a Seraph (upped)
The, you are essentially taking 12-8=4 damage every turn.
But... stalling them make no sense to me. EM? Not that important in pvp, and for arena, survival is much more important, as opponents has a head-start with more quanta, more cards, and more hp.
A vampire-heavy monodark would have done as well if not better. Really, eclipses are more practical.