B/R Vamp Deck: Blood Drinkers. Deck Critique

[Zidarose]

Lands: 20
Darigaaz’s Caldera x4
Dragonskull Summit x4
Mountain x6
Swamp x6

Creatures: 28
Gatekeeper Of Malakir x4
Olivia Voldaren x2
Stromkirk Noble x4 – likely to be cut due to rarity & cost
Vampire Nighthawk x4
Bloodcrazed Neonate x4
Bloodline Keeper x2
Guul Draz Vampire x4
Pulse Tracker x4

Spells: 4
Feast of Blood x4

Enchantments/Curses: 6
Curse of Stalked Prey x4
Bloodchief Ascensionx2

Artifacts: 4
Blade of the Bloodchief x4
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Okay, that's the idealized version of the deck. I stand by the potential change just to have something that will work to bolster the whole crew very well with Cursed of Stalked Prey. I favor the Caldera because while it does bounce a land, it doesn't come into play tapped. There were originally Four Piranha Marsh to back it all up and increase early damage but I want to see how it functions with more readily available mana.

At present I have ~61% of the deck:
Lands: 12/20
Darigaaz’s Caldera x0
Dragonskull Summit x0
Mountain x6
Swamp x6

Creatures: 17/28
Gatekeeper Of Malakir x3
Olivia Voldaren x0
Stromkirk Noble x0– likely to be cut due to rarity & cost to -> Rakish Heir x2
Vampire Nighthawk x3
Bloodcrazed Neonate x4
Bloodline Keeper x1
Guul Draz Vampire x3
Pulse Tracker x3

Spells: 4
Feast of Blood x4

Enchantments/Curses: 3/6
Curse of Stalked Prey x2
Bloodchief Ascensionx1

Artifacts: 2/4
Blade of the Bloodchief x2

[Void Elemental]

Stromkirk Captain for the Noble spot? Vampiric Fury could be game.

[DatAsh]

Why are you using Darigaaz's Caldera? Why not Blackcleave Cliff's or something useful? You don't need this. Heck even Savage Lands would be better.

[Zidarose]

The deck actually came together as I designed it for once!
(Potentially Sans Olivia Volerna, whom I'm considering replacing with Ascendant Evincar)

Darigaaz's caldera has a unique property which has been useful to me before. While I need to return a land to my hand, it enters play untapped. Done right, I can easily pull mana from a land before I bounce it and then use it to cast a spell. Blackcleave cliffs ONLY enters play untapped if you control less then 2 swamps or mountains. I'd rather deal with the bounce than the wait.