Magic: The Gathering is very fun to play but it is hard to dissect the nature of "fun". One of the key areas that Magic does very well is that it avoids power creep, which is the tendency to create ever more powerful cards thus obsolescing older cards. Cards from Alpha can easily play against newer sets like Innistrad. (Obviously some of Magic's older cards are costed much too high and I hate paying more than 3 for a 2/2.)
One way to avoid power creep is to not make cards clearly better. What I mean is, if a cards does X, avoid creating cards that do X plus something more. Try to create cards that are similar to X but also have an ability that is sometimes better and sometimes worse depending on the situation. Make the player struggle (in a good way) to figure out what is the card's overall power level and in what situations is it inferior and superior to previous cards.
Minimizing power creep also keeps vintage formats healthy. Vintage players would hate to buy card X only to find out card Y is noticeably better. As long as you give cards the right amount of variation, it keeps the format "healthy" with a diverse assortment of winning decks.
Obviously using Forge is a great way to see a wide selection of Magic's 14,000 cards. (Some of you may have 8,000+ different cards in your collection but most of us don't.) Magic: The Gathering is the result of relentless playtesting and the active avoidance of power creep. I remember reading that only 10% of all cards that Wizards creates during development are actually printed, which means that we, the public, only see the top 10% cream of the crop. Often you can't create the best cards without creating plenty of bad ones.
While it may seem like Magic "just happens" to minimize power creep, I'm sure that the "powers that be" are always on the lookout for it. "Because if you aren't looking for it, you'll probably fall in it", which is a random saying that I just made up.
So in closing, power creep bad, Magic good, and if everybody had a million dollars the economy would fix itself. (I'm joking of course because if everybody had a million, a million wouldn't be worth anything because money is based on the idea of scarcity. Hugs are not based on scarcity: wtf?!?)
Forge and other free programs are based on the idea that scarcity doesn't matter and that people will donate free work/time if the project is good enough. The cool thing is when free projects like Linux and Firefox actually generate real jobs and revenue transforming a "free project" into something that actually boosts the economy.
On a side note, Forge will never generate money because of licensing issues. This isn't a slam again Wizards, just a fact of life. Wizards owns Magic and no one else can use their IP (intellectual property) without their permission, just like your fan-made script of "Star Wars 3.5: The Death of Jar-Jar Binks" is never going to get made because George Lucas won't authorize it.
I've never seen the unauthorized edit of Star Wars which is colorfully called the phantom edit which minimizes the Jar-Jar problem since less Jar-Jar is always a good thing. At least Lucas didn't make Jar-Jar a Jedi, "Me-sa going-to wield-a lightsaber-sa?
Next time I'll discuss how Mark Rosewater uses Hitler's still-living brain to generate new cards and to warp the space-time continuum so that Roseanne is always stays on the air. (Either you do get the joke or you do not. There is no try.)
....and I'll stop there, which also happens to be my craziest rant.
"Power creep" reminds me of the song "Creep" from Rock Band..."But I'm a creep, I'm a weirdo..."
[End Transmission: Again, sheesh...does this guy ever shut up?]
It's easy to be random at 4am.