Making a Set

I've been reading through the Nuts and Blots articles from MaRo. I think it would be a great benefit to me to make a magic set from the ground up. Before I make the design skeleton, I first have to decide what the set is going to be about. What is the Vision for the set?
Step 1, list the things I like.
I have a luxury that R and D don't have, which is that this doesn't have to connect to other magic products in any real way. It can be about anything interesting. I'm going to try to stay to things that are printable. The set won't intentionally include storm or dredge, but this is more from a story perspective. So I get to just list things that I find compelling:

Phyrexians
Tezzeret
Graveyard mechanics
Multicolor, specifically enemy colors
Factions
Sphinxes
EDH
Enchantment Creatures

Ok that's a good list. Obviously not all of these things can work together. How many can I weave together into a complete picture?
Well Tezzeret was last seen on New Phyrexia, Sphinxes are a large part of Esper, where Tezzeret is from. Esper/Alara is well known for its multicolor theme, and there's factions aplenty! Its also probably the most important block for EDH. The introduction of tri-color legends that were cheap and interesting really drove a lot of interest in the format. Having Esper and Phyrexians is going to necessitate a lot of artifact creatures, so that means I have to cut Enchantment Creatures. It also doesn't play particularly well with the idea of the graveyard as an overall theme, but there might be room for a golgari mechanic that uses the yard in some fashion.

Ok. It looks like the Phyrexians are going to invade Alara. Why would they want to do that? Tezzeret must have informed them about Etherium. Phyrexians are all about perfection. They are going to want the perfect metal to compleat themselves. When last we left Phyrexia Elesh Norn had become the dominate force on the plane. Tezzeret was still present, but the Praetors were not a fan of him. I'm just going to baldly state that Elesh Norn is the Mother of Machines. Tezzeret was tortured into giving up the location of Etherium, The Phyrexians dissect Venser and figure out how to make a ship that traverses the planes. This leads to a cool trope to play into, the alien invasion. We know the Phyrexians are going to attempt to convert whatever plane they land on, but unlike Mirrodin, they won't literally be in the core of the planet here. They will have to grow from their initial landing. This might be too similar to the structure of Scars block anyway though. The other way to go is that they launch a large invasion force. I'd prefer the phyrexian to non-phyrexian % to be closer to 50/50 since this is a two set block, and the gradual over taking of a plane has been covered. Ok, going with a larger invasion force and being deep enough into the war that we've got a good amount of Phyrexians.

So the Phyrexians land on Alara in force to lay claim to Etherium, Sangrite, and the enormous mana source that is the Maelstrom. Alara has to marshal themselves to throw them off. Specifically, this is a threat to Bolas and his machinations. 

What mechanically defined the Phyrexians? 
Infect
Phyrexian Mana
Conversion
Biomechanical
Adaptive

The Phyrexians are essentially a more nightmarish version of the Borg, They consume and adapt, They re-purpose and change themselves based on the make up of what they consume. They function less like an army and more like an organism. They exploit the resources of others to make more of themselves. 

What mechanically defined Alara?
Multicolor
5 separate societies   
Cascade
Colored Artifacts
Exalted
Unearth
Devour
5 Power matters
Domain
Hybrid Mana (sparingly) 

Alara was defined by the split nature of the planes. Now that the planes are conjoined, they have been in chaos warring against each other. The hapless nature of most of the peoples of Alara is evident in their inability to see the cataclysmic crash of their lands together. However, the specialized nature of the various planes keeps them from working together. Despite this, the 5 conjoined planes have an embarrassment of riches, and more mana of the various colors than anywhere else. That's why Bolas wanted it for himself in the first place.

So the vision is Tezzeret convincing Phyrexia to use their limited planes-crossing technology to invade Alara. This pits Bolas against Phyrexia with the rest of Alara caught in the crossfire. The thing I keep thinking is how interesting it would be to have multicolor phyrexian mana cards. Obviously the Praetors of New Phyrexia are pretty well established, but if they needed to send ships, it would make sense for them to send lieutenants in place of themselves. Then I can take some of the characters mentioned in the New Phyrexia flavor text and make them into two-color Praetors for the Phyrexian leadership. This lets Phyrexian mana come back, but only be on multicolor cards, demanding at least 4 life per card. That should keep it more taxing than its prior incarnation.  

Ok, I'm excited. I'll be back next week with a design skeleton.