1. How many people can play?
Is a match between two players? Or can more than two people play a match at a time, in which case what should the upper limit be?
2. What's the interface?
Are cards displayed publicly somehow (on the ground or a table)? Or does each player get a special pop-up interface GUI with some shared display area so that other players can see any public cards, as well as a private area so that only they can see their private cards?
3. Can spectators watch?
It might be nice if there were an option to allow spectators to watch a game somehow. If both/all players of a session agree, spectators would get their own interface allowing them to see the public cards played in a hand.
4. Should players be allowed to wager on the outcomes of matches?
If so, should there be an upper limit on wagers?
Note: This item and the next one are dicey (so to speak) in that there may be state/regional, federal/national, or international laws regarding "gambling" that might potentially be applicable to games of chance even set solely within virtual worlds. In other words, there are possible legal issues above and beyond any technical/design aspects of wagering on card-based minigames inside a MMOG.
5. Should spectators be able to wager on the outcomes of matches?
If so, does there need to be an interface insuring that wagers are guaranteed? (Sort of like the Secure Trade Window, except that the transfer doesn't happen until the match is decided.) Or should spectators be on the honor system?
6. How are cards obtained?
Does everybody get a deck for free? Or are there special cards that can only be obtained as individual items? If so, which of the following ways of obtaining cards should be offered:
- dropped as loot
- quest reward
- crafted or produced by magic
- given as mark of divine favor
- purchased from public market
- traded/purchased directed from other players
- found through exploration of new/hidden places
This could be dependent on the rules of the game, but it's worth considering. Are all cards necessary to play the game stored individually in a player's inventory? Or are all cards stored as a full deck in every player's inventory? Or are there standard cards that aren't actually stored anywhere; they're just assumed to exist and get pulled out of nowhere when a game starts?
8. Can the game only be played in certain locations or at certain times?
Is a special "table" required to play the game? Or can two people meet up out in the wilderness and fire up a game?
9. Is tournament play possible?
To ask this question another way, should the results of matches be public information?
The idea is that players would be able to agree that the results of their games would be tracked globally (across a shard, at any rate). Basically there'd be a leader board for whoever wanted to participate.
The best players each real-time month (whether "best" is defined as # of games won, or percentage of games won, or -- my preference -- amount of money won) would then be invited at regular intervals to participate in a monthly tournament, with nice items or possibly even a few months of prepaid HJ game time as a reward for winning the tournament.