I've decided to try a WW build without using the Tax/Rack engine, since the results haven't been that good. Thus, I've decided to center around the Empyrial Armor/Cataclysm combo, along with a mana curve.
4 Savannah Lions
4 Mother of Runes
4 Soul Warden
4 White Knight
4 Soltari Priest
2 Paladin en-Vec
1 Pianna, Nomad Captain
1 Leiutenant Kirtar
4 Empyrial Armor
3 Swords to Plowshares
I run more than the usual amount of creatures due to the loss of Tax/Rack. Tithes are for deck thinning and recovering from Cataclysm. The two legends are there pretty much just for fun; they should probably be two more Paladins or possibly Mystic Crusaders. I would run Wastelands, but I can't seem to find room. I might cut the Tithes for them.
I have a WW deck extremely similar to this , except I don't use Empyrial Armour or Cataclysm and instaed just go for mass creature pump via Crusades and Glorious Anthems. Cataclysm and Empyrial Armour isn't an actual combo. Cataclysm (almost entirely sure on this) in order for it to work each player MUST have all 4 of those types of permanents in play in order for it to do anything. I would consider taking it out for something much better. Using Pump Knights wouldn't be such a bad idea either.
Cataclysm, 2WW, Sorcery, Exodus Rare
Each player chooses from the permanents he or she controls an artifact, a creature, an enchantment, and a land, then sacrifices the rest.
Cataclysm will work. If a player cannot choose one of those types, he just doesn't get to choose one. It works fairly well with Empyrial Armor. Usually, however, (IIRC) you'd want to have the Armor on a Shadow dude so he's most efficient against the one dude your opponent would have left. When you Cataclysm in this deck, you lose the handful of utility creatures (Mom and Pianna) you are running. You may want to consider running Monks in addition to Priests. Also, the choice of Tithe and StP is great w/ 'clysm, as they only cost one.
It looks like a fairly solid deck.
Color= White Type= Sorcery Cost= 2WW EX(R)
Text (EX+errata): Each player chooses from the permanents he or she controls an artifact, a creature, an enchantment, and a land, then sacrifices the rest. [Oracle 1999/05/01]
If you control a permanent with more than one type, you can choose that same permanent for more than one of the choices if you want to. [Barclay 1998/06/10] This makes it possible to select a Brass Man as both your artifact and creature, and then select a land and thereby keep only two cards. You probably won't want to do this often, but it is an option. [D'Angelo 1998/08/19]
If you control a permanent with more than one type, you can choose that permanent to be the representative of either type. This makes it possible to have more than one creature (or other permanent type) in play. For example, if you select a Scryb Sprite for your creature and a Brass Man for your artifact, you get to keep both of these creatures. [D'Angelo 1998/07/23]
The permanents to save are chosen on resolution. You do not choose them when announcing the spell. [WotC Rules Team 1998/08/01]
The current player makes their choices before the other player. After both players make choices, all the sacrifices are done simultaneously. [D'Angelo 1998/11/04]
Nothing about all the permanents having to be in play If it said "target creature, target enchantment, target artifact, and target land," then it would be as Martin said. However, it doesn't say that. All you need to cast a spell is legal targets, and Cataclysm targets the players rather than permanents.
Hrm. You are right about the MoM and Pianna. MoM's ended up being rarely cast, and Pianna's bonus is nil with only one creature in play. Here's the changes.
-4 Mother of Runes
-1 Pianna, Nomad Captain
-1 Lieutenant Kirtar
+4 Soltari Monk
+1 Paladin en-Vec
+1 Swords to Plowshares
Would Erase be a good alternative to Disenchant? It might be better since it's only 1 mana and removes the enchantment from the game.
aura blast might be better (if you also run null rods) b/c it's a cantrip