You guys need to do a stupidity check

Seriously. I am all for modding in general, and the collective work done on stand-alone play servers and deck builders discussed on this site, and especially the work done to generate the Manalink ISO, is truly impressive. But...
DotP/Steam is an official Wizards product, and hacking that is like trying to hack MtG:Online, it is doomed to failure, and will eventually bring down the wrath of the gods (e.g. people will get their Steam IDs banned, and lose not only the use of DotP, but all other Steam-purchased software). The only reason they aren't cracking down harder on you immediately is that the presence of hacked client files isn't their biggest problem right now; the console port is itself very buggy (read the Steam forum to see how bad it is), and they are struggling to get major issues patched. Once the dust settles from that, they will be coming your way, mark my words.
DotP is client-server, and all adjudication of deck legality is on the server side. You can add all the new card logic you want on the client side, the server will still ignore your work. The only thing of significance I've seen discovered here is the existence of an exploit to force-unlock all official cards in the game. This is something you're either supposed to "win" by progressing through the challenges, or by paying Steam for fast unlocks. It's a cheat, but no one is going to lose sleep over it, and it sounds like they may have already patched it out. Steam keeps your unlock history in the cloud anyway, and if there is a client-server mismatch, they can just wipe the client files and force you to start over. Again, this is probably not being enforced just yet since they have bigger bugs to worry about.
DotP isn't supposed to be a full-fledged implementation of MtG. It is a "quest" game using MtG dueling with the specific intent of introducing basic game mechanics to new players who might otherwise be intimidated by the complexities of the full game. It purposefully restricts itself to the M10 starter decks plus a set of additional pre-constructed decks designed for the quest game. Open play using the starter decks and the additional quest game cards/decks you have "won" is implemented, but there is no deck builder, also on purpose, to keep things simple. The card selection is also designed to keep things simple. If you want to play with any other cards, and/or if you want to build your own decks, Wizards expects you to either (a) go to MtG:Online, or (b) find play-aids here. For obvious reasons they prefer (a), but they continue to tolerate (b), as long as idiots don't try to hack their servers...
Please let DotP serve its intended purpose, to help draw new players into the MtG world. Some of them will migrate to MtG:O, others will eventually come here instead. Isn't that what you would rather see happen? Anything that disrupts their server will ultimately cause new players to quit in frustration, and then everyone loses. Yes, the interface looks spiffy, and yes it would be cool to use it in place of the existing options, and "maybe" Wizards will migrate MtG:O 4.0 to it, but you can just as easily mod the other UIs people are using now to more closely approximate what DoTP looks like. And if you really really need to have that deck builder with all the latest official complete sets to play with >NOW<, I suggest you browse elsewhere in these forums, you'll be pleasantly surprised at what you'll find.
One other thing. DotP/Steam has a ranking system, it mirrors the one used on Xbox Live. Both new and experienced players are using DotP and care about the rankings. Considerable effort has been made to devise a match-making system within open play to help players find others near their own strength, at least when using the fixed card sets available. Many of the players care more about the ranking system than any other part of the game. Hacking client files to influence your deck status can be viewed as a major cheat intended to break the rankings, and a lot of players will be seriously pissed when they find out that's happening. Steam's anti-cheat software isn't designed to trap something like that (yet). It's a good way to make a lot of enemies in the MtG community.
DotP/Steam is an official Wizards product, and hacking that is like trying to hack MtG:Online, it is doomed to failure, and will eventually bring down the wrath of the gods (e.g. people will get their Steam IDs banned, and lose not only the use of DotP, but all other Steam-purchased software). The only reason they aren't cracking down harder on you immediately is that the presence of hacked client files isn't their biggest problem right now; the console port is itself very buggy (read the Steam forum to see how bad it is), and they are struggling to get major issues patched. Once the dust settles from that, they will be coming your way, mark my words.
DotP is client-server, and all adjudication of deck legality is on the server side. You can add all the new card logic you want on the client side, the server will still ignore your work. The only thing of significance I've seen discovered here is the existence of an exploit to force-unlock all official cards in the game. This is something you're either supposed to "win" by progressing through the challenges, or by paying Steam for fast unlocks. It's a cheat, but no one is going to lose sleep over it, and it sounds like they may have already patched it out. Steam keeps your unlock history in the cloud anyway, and if there is a client-server mismatch, they can just wipe the client files and force you to start over. Again, this is probably not being enforced just yet since they have bigger bugs to worry about.
DotP isn't supposed to be a full-fledged implementation of MtG. It is a "quest" game using MtG dueling with the specific intent of introducing basic game mechanics to new players who might otherwise be intimidated by the complexities of the full game. It purposefully restricts itself to the M10 starter decks plus a set of additional pre-constructed decks designed for the quest game. Open play using the starter decks and the additional quest game cards/decks you have "won" is implemented, but there is no deck builder, also on purpose, to keep things simple. The card selection is also designed to keep things simple. If you want to play with any other cards, and/or if you want to build your own decks, Wizards expects you to either (a) go to MtG:Online, or (b) find play-aids here. For obvious reasons they prefer (a), but they continue to tolerate (b), as long as idiots don't try to hack their servers...
Please let DotP serve its intended purpose, to help draw new players into the MtG world. Some of them will migrate to MtG:O, others will eventually come here instead. Isn't that what you would rather see happen? Anything that disrupts their server will ultimately cause new players to quit in frustration, and then everyone loses. Yes, the interface looks spiffy, and yes it would be cool to use it in place of the existing options, and "maybe" Wizards will migrate MtG:O 4.0 to it, but you can just as easily mod the other UIs people are using now to more closely approximate what DoTP looks like. And if you really really need to have that deck builder with all the latest official complete sets to play with >NOW<, I suggest you browse elsewhere in these forums, you'll be pleasantly surprised at what you'll find.
One other thing. DotP/Steam has a ranking system, it mirrors the one used on Xbox Live. Both new and experienced players are using DotP and care about the rankings. Considerable effort has been made to devise a match-making system within open play to help players find others near their own strength, at least when using the fixed card sets available. Many of the players care more about the ranking system than any other part of the game. Hacking client files to influence your deck status can be viewed as a major cheat intended to break the rankings, and a lot of players will be seriously pissed when they find out that's happening. Steam's anti-cheat software isn't designed to trap something like that (yet). It's a good way to make a lot of enemies in the MtG community.