I like this concept, but it seems like it still needs a fair amount of work to be done creating the Shop (a google doc of some kind I'd assume) and a method for determining the specific booster contents. I'd be willing to run it once it gets finished though.
You're right in saying that the Card Shop needs work, but I would really need some help in getting it done if you were to run it. I want to make it player-friendly as well a PvPO-friendly.
I was leaning towards the following percentages for getting rare cards:
Whether a player gets two or three rare cards: 70% for two -- 30% for three
Whether one of those rares is a mark or nymph: 5%
As for the way a player knows what cards are in the card pools, I agree that there should be some form of google docs (like the vault) for each player.
I know I'm probably trying to do too much, but why not think big?
It seemed to me like the buying packs would be completely random (generating based on a card list?).
Only problem I see with that is there needs to be some sort of record thread of everything. A la dog pit, perhaps?
Yes the cards you get are completely RNG'd. The way you use/sell/upgrade them is up to you.
For the other question, refer to my reply to Sot.