My initial plans alluded to above were as follows:
Aim to have a creature card for most units in the game, a noncreature card for most spells, and artifacts or enchantments for some buildings as make sense.
Zerg unit cards should be green or black. The Zerg are the best example of a green-black antagonist I'm aware of.
Protoss unit cards should be white or blue. The Protoss are clearly very white, with their castes, judicators and warrior-priests; and some aspects of the Protoss flavour are quite blue, especially their psionics.
Terran unit cards should be mostly red, with some in other colours. The Terrans have a feeling of improvisedness, hasty recklessness, and short-tempered militia that I think fits best in red. But I was expecting to put a few units in other colours.
I note that these colour divisions aren't original - I've seen the topic discussed in a couple of places, and these seem generally agreed as the colours the StarCraft races correspond to, with certain variations.
Spells for each race should be primarily in the colours just mentioned, but they don't all have to be.
Named characters such as Raynor, Duke, Fenix etc are Legendary Creatures. Kerrigan may be a Legend or a Planeswalker.
I might save the Brood War units and technologies till an expansion set, or include them in this set. I won't be including units or technologies that only exist in StarCraft II.
I'd like for it to be a viable strategy to draft mono-Zerg, mono-Terran, mono-Protoss, but for it to also be viable to draft some overlap between the races.
Here's my FAQ-style explanation of the new keyword abilities.
New keyword abilities: Cloaking and Detector
Cloaking and Detector are keyword abilities that all three races have. Creatures with cloaking are invisible to most creatures. The only exceptions are creatures with detector: creatures with detector can see cloaked units, but no other units can. In game terms, this means that creatures with cloaking can't be blocked by creatures apart from ones with detector; they can't be dealt damage (including combat damage) by creatures apart from ones with detector; and they can't be targeted by activated or triggered abilities of creatures without detector.
This doesn't really tie in with how cloaking and detector work in game; in StarCraft, as long as you have at least one unit with detector, all units in range can attack and block. This is particularly relevant because of how few detector units are viable in combat. --Angoel
Mmm. True. The flavour of this conversion is a bit unclear about how "close" to the current combat your other units are. But if I'm allowing Splash to hit any unit, I guess I should make it that defender controlling any detector works. Thanks for the comment; I'll have a think about how to fix this. --AC
Ghost, 1U Creature - Human Soldier, 1/1 1: Ghost gains cloaking until end of turn. (It can't be blocked, damaged or targeted by creatures without detector.)
If Ghost attacks after having activated its ability, the only creatures which can block it are creatures with detector.
If Ghost blocks after having activated its ability, the damage assigned to it by its attacker will be prevented unless that attacker has detector.
If Ghost has activated its ability, any activated or triggered abilities from creatures without detector can't choose Ghost as a target.
If Ghost hasn't activated its abilities, it can be chosen as the target of activated or triggered abilities from creatures without detector. However, once those abilities are on the stack, if Ghost's ability is activated in response, Ghost will be an illegal target when the other creature's ability resolves, and so Ghost will be unaffected.
All spells, including Auras, may target creatures with cloaking as usual. Cloaking only protects against other creatures.
Because splash is an ability of the creature, splash damage from creatures without detector can't hit creatures with cloaking. (That's the consequence of the rules as written. I'd like to change this though if I could find a sensible wording for cloaking that allowed this.)
New keyword ability: Shield
Almost all Protoss units have a new ability called Shield. This is similar to the absorb ability from Future Sight, but behaves differently when multiple sources want to damage a creature with shield, such as when one is blocked by multiple creatures. It's written with a number, for example "shield 2". Any time damage would be dealt, by any source, to a unit with shield 2, the first 2 of that damage is prevented.
Have you considered instead giving all creatures Wither (maybe with 0,-1 tokens instead of -1,-1 tokens). It would work better with the fact that, once damaged, repair of protos units is impossible, and the shield regeneration is more similar to the way that damage is cleared at the end of turn. --Angoel
And having Shield be something like "The first N damage dealt to this is dealt as though its source didn't have wither"? Hmm... I was treating the difference in the way damage is handled more as an inevitable consequence of adapting the game into a different medium. There will always be some such (for example, I've not given ground-to-ground units text like "Prevent all damage ~ would deal to creatures with flying"). Note that Terrans and Zerg can recover all their lost hit points (via Medics or SCVs, or Zerg's slow natural healing). I'd prefer not to have universal text I need to have on all cards - it's vexing enough having to make text-box space to put shield on every Protoss, including the Legends.
I can see the motivation for your suggestion, though. As you say, Protoss shield regeneration, and Zerg healing, are reminiscent of how damage goes away at end of turn. I'll see if I can come up with a way to match these up that I'm happy with, but I don't think there's a huge problem with the current implementation. --AC
Dragoon, 3W Creature - Protoss Warrior, 2/2 Shield 2 (Prevent the first 2 of any damage that would be dealt to this.) Reach
If a spell is played that deals 3 damage to all creatures, 2 of the damage to Dragoon will be prevented. Dragoon will take 1 damage, and survive.
If in the same turn, Dragoon then gets into combat with a 3/3 creature, another 2 damage will be prevented. Dragoon will take 1 more damage, at which point it will have lethal damage and be put into a graveyard.
If Dragoon is blocked by two 2/2 creatures (without first strike), since all the combat damage happens at once, only 2 of it is prevented. The controller of Dragoon chooses which 2 damage to prevent. The rest is dealt all at once, at the same time that the creature with shield deals its combat damage.
If Dragoon is blocked by a 2/2 creature with first strike and a 2/2 creature without first strike, the shield ability will prevent all of the damage that would be dealt to Dragoon, since it's dealt as two chunks of 2 at separate times.
New keyword ability: Splash
Splash is an ability a number of creatures have. Whenever a source with splash deals damage to a creature, it gets to deal extra damage to a third creature, if there are any. Every means of dealing damage, including combat damage, will trigger splash – apart from splash itself.
Mutalisk, 3B Creature - Zerg, 3/1 Flying Splash 1 (When this creature deals non-splash damage to a creature, you may have it deal 1 damage to another target creature.)
You can choose any targetable creature for the splash damage, apart from the creature with splash itself and the creature which was damaged to trigger splash.
Because splash is an ability of the creature, you can't choose a creature with cloaking (unless the creature with splash also has detector). (That's the consequence of the rules as written. I'd like to change this though if I could find a sensible wording for cloaking that allowed this.)