While I'm not an expert or on the Dev staff for this application, the Developer and I have had a few communications in the past, I've worked with the custom card stuff enough, and I'm an Open Source Developer myself. I feel able to answer a few queestions...these are in no particular order.
Fiilters for Older/Modified Formats:
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I believe what you're asking for here is to be able to pull "2010-2011, Diamond and Pearl -> Heart Gold Soul Silver" or something like that.
While this IS possible it's not the focus of Redshark to play games in past formats. The possbility IS there to play prior format or unlimited format games through the use of the drop down selector setting the format from Modified (which has specific meaning to the version of code you are running and the date it was released on) to "unlimited" which allows the use/selection of any card. TBH This is only a filter, there's nothing stopping you from creating a deck with any card you wish in it.
Adding a filter for each format is extending a feature that is not intended to be widely used. The basis for the reason RedShark exists (same as the other online Pokemon Games) is deck testing relivent decks within the current format with a wider audience than those people in your neighborhood or league. While it IS POSSIBLE to test any deck with any card, extending the filter may not be the developer's best use of time...especially since if you are interested in playing a prior format you should already know what those cards are.
Adding Additional Cards not currently Released
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Again, the feature is ALREADY THERE to add whatever cards you want to your Custom Cards Database and play with those cards. You CANNOT do this online, however, for VERY good reasons.
1) You can't pass cards along the network, everyone has to have the same cards to play a game with each other. This is not "client server" technology: There is no maintained centralized database of cards that the networked clients are accessing (allowing the developer to control what is what). Allowing Custom Cards to work over the network would require both parties to have the same Custom card database, and then when 1 person's translation is off or missing or the cards are mis-setup, something odd can happen...at which point the developer starts getting support requests for broken software which are really client side problems. Believe me when I tell you even the most basic of problems and the most obvious of "user" issues will suck up 10s to 100s of hours of your support time. Best to avoid these completely. This is why "CUST" cards form the cust card database are not read during network play.
If, instead, you allowed each user to modify the base database and/or allowed Custom cards, you could be encouraging cheating.
2) The focus is on current format testing, not future/past format testing. Again, the focus of the application, as with ALL online Pokemon Applications, is on testing the cards in THIS format, not previous and CERTAINLY not future formats. Focusing on only leagal playing cards distributed from a centralized source (with the download of the app) without ability to be modified ensures that all online games are played with the same consistency.
Specifically related to Rules Questions: what happens when you have the japanese translation for a card in the game and there's a question: who solves the rules issue? There are no resources to go to to verify how the card is actually suppsoed to be played because it's not yet been RELEASED in the US. The Rules team can't answer whether Pokemon X's ability affects Pokemon Y's attack in way Z because the card isn't ours to transalte. This creates inconsistency in game play, game to game, when you and your oppoent decide one thing and in the next game your opponent won't agree to it.
3) Playing cards that are 6 months out does NOTHING for your pokemon play. Having your networked opponent able to build decklists that are out of current format doesn't help your deck testing in this format. While it's fun to play cards that aren't released yet, we don't allow it in leagues or tournaments for the same reason it's not allowed here...for as fun as those cards look to play they're NOT RELEVANT cards. You don't know WHEN you'll get them, you don't know if the actual translations are correct, and you don't know how conflicts will be ruled.
Note also, that technically Redshark breaks copyright and Intellectual Property law. The developer of Redshark does NOT work for Pokemon, this is NOT their application. He does NOT own the copyright or intellectual propery rigths to any of this and it IS a violation for his application to exist without permission from the copyright holder. It's ALLOWED to exist by the Pokemon Company LTD. because it serves them to allow his software to work. More people playing the game allows more visibility to The Pokemon Company LTD. The software hasn't been shutdown because it's not worth it to do so and actually is beneficial to exist.
That may not be the case if the developer starts putting unreleased cards into his software. It is my understanding that The PokeBeach has gotten in trouble time and time again for their release of cards and information that is NOT public knowledge and that MAY BE under leagal NDA (NOTE: I need to be clear that this is hearsay, I have no first hand knowledge of this being the case). While the site is typically DEAD ON with it's information, the public posting of that information, in at least some cases in the past, may be actually Illegal (were someone to want to push the issue). This is NOT something you EVER want to be involved in as the developer of an open source piece of software.
Best practice is to follow what the Pokemon Online software does: When it releases new cards to your target audience, you do as well...and that precludes "future" cards from being added to the software.
The "Lag" of Redshark Development
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What StormFront points out in his post is actually dead on, many cards and intracies within Pokemon actually require the update to the SOFTWARE to support the cards, not just the card database. From the large and broad (how do you impelement a new Dragon Type in the software) all the way down to the Minuta (how does the card filter support a new set designation) there are changes that each version of the software needs to make to support the new set of cards.
Getting a group of people (after talking with the developer, it's not the card scans and card entry that's a problem here, that's usually done pretty quickly) to update a spreadsheet properly is not a major problem. It's the code and release that becomes an issue.
Back when this software was hosted by the beach, many times the lag in update was not due to the release of the software, it was simply due to the beach's admins making that software available to the public by updating their links. Sites like that are VERY busy, admins are few and far between, and always volunteer. Given the challanges inherent in running a large site such as this one or the beach or others, sometimes just getting to doing something like releasing a new piece of software can take months.
Opening Redshark to Community Work
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While, as an OSS Developer myself, I appreciate the concepts and interest in opening a piece of software like this to the Pokemon Community to maintain and build, there are some unique challanges in sutuations such as this that make this kind of idea problematic.
First and foremost, any ongoing open source development effort requires a leader. Without the drive of an individual or group of individuals the project tends to fall apart. While a single developer with local control can tend to produce a product such as this efficiently, getting more than one developer, more than one cook in the kitchen so to speak, can bring a project to a crashing halt as the "helpful" developers take the project in a metric ton of different directions.
And again, there's the whole Copyright concept. There's a possibillity that a larger group of people implementing some of the ideas, even in just this thread, could technically get the software shutown and removed from the market simply by making the application into something that Pokemon consideres a hinderance to it's game or it's own offerings instead of a help. With one developer, one central point of contact, one point of control, Pokemon can feel more comfortable: If they ever want to shut it down there's only one place to go to. An OSS Project has hundreds or thousands of people, any of which could do something to give Pokemon a bad name.
What you're asking to be able to do is get ahold of the card database and update it in the first 24 hours of a pre-release (or in some of your cases you're talking about months and months ahead of time) figuring that's all there is to the maintenance and release of this application.
There's a lot of missing thought about copy right protections, release strategies (even who should be making an offical build and where it should be posted can become large issues and items of discussion in public environments), and other technical and design details which user communities are NOT good at figuring out. That's not to say there aren't many successful OSS projects out there, it's just that there are some concerns and constraints here that the developer might have about making it into one.
). I had some ideas that I hope are simple (and desirable) enough to be worth consideration.