It's worth a read. Adam's a sharp guy with knowledge of a lot of systems and a wide range of playstyles, including some less common ones such as online play, and he goes into this eyes open with both fists full of dice, and comes out the other side having had a great time. So much so that I think he surprised himself a little.
Now, I suspect that the thing that Adam is overlooking in his analysis is the impact of the quality of the GM but that can be forgiven pretty easily. A lot of the positive things he speaks to (fruitful constraints, speed of play speed of character creation and so on) are things I've been enjoying in some new games and are also things I'm keeping in mind for the Heartbreaker project. But one bit in particular stood out and made me think, and let me quote it here.
Second, there are very few tactical options built into the rules: attack with a melee weapon, attack with a ranged weapon, cast a spell (if you have any), or run away. Of course, the game expects players to make up tactical options that aren't in the rules and expects the DM to accommodate them; there's just no rules support for this.
He is, of course, absolutely right. It also pushes players toward creativity, though how it does so is interesting to consider. On one hand, by removing the amount of thought that goes into choices and rules, it frees up the player to be more creative. On the other, by offering the player so few interesting choices, the player is pushed to be creative if only to stave off boredom. There's more than a little truth to both of these explanations, and I think the real power comes from the combination of them.
Even more I think he's put his finger on the pulse of something incredibly important. But while it's a signifier, it's not an answer. See, this issue - how many choices and how explicit the choices players have - is incredibly important, but it's also one that has no one answer.
See, explicit choices with mechanically supported effects really are quite cool. They're fun. They keep players from feeling like they have no options, and they help them feel like their actions matter because they can see the mechanical impact, right there at the table. That's powerful. It also protects players from a capricious GM whose interpretation of things may or may not end up favoring them.
But on the other hand, it can get overwhelming. 4e has a long list of explicit actions available (some, like powers, are character specific, others like drawing a weapon, are universal). It is technically possible to take an action outside of that list, but because the rules options are so thoroughly detailed, it's not easy to think in those terms. The stunt system exists to mitigate this, but as much as I love it, it takes a mode of thought that is different than is encouraged by normal play.
And that, I think, comes back to the rub. Each approach has real flaws of too much and too little structure, respectiviely, but each approach can be made powerfully playable by a specific set of GM skills, skills that have a curious amount of overlap.
This may seem cynical, but the straight rules adjudication element of GMing is pretty easy to learn. Even if the game has reasonably complicated rules, mastery is just a function of study and attention. Now, just because it's easy doesn't mean its unimportant - this is the foundation for a lot of what the GM needs to do, and flaws will propagate - but this is the very basics. It's the kiddie slopes.
One of the first real challenges to GM skill comes when things go off the rules. Not merely in terms of how to adjudicate things outside of the game's sphere (like how to run non-fight encounters in D&D) but in things specifically within the games purview, such as fights. In one of those cycle of knowledge ironies, experience can end up looking like a novice. A GM who doesn't even grasp the game will allow the players to do anything they describe and just fake it. The GM who really knows the game will do the same. But the GM in the middle often creates an invisible barrier that separates things within the rules from things outside of them, and that barrier can be hard to pass through.
Note. this is rarely poorly intentioned or intentional, it's just a function of learning and perspective. If the GM can make rulings off the top of his had, but has to pause for a few minutes to check the book every time players go off the playbook, that's a barrier. He's training players to stick to the playbook to avoid inconvenience. Similarly, if the GM's on the fly rulings are unreliable or problematic, that's another barrier. Players will play to avoid triggering those.
Each type of game leans to its own kinds of barriers. Lighter games have barriers of uncertainty - in the lack of rules support, it an be very unclear how an idea will be expressed. Heavier games have lots of tools for how to express things mechanically, but they create a higher cognitive barrier for going off the rules. But in both cases, how much of a problem this is ultimately comes down to how well the GM (and players) handle that barrier.
On one level this is a long, roundabout argument for the importance of GM skill, which some would probably point out that an argument that doesn't need to be made. And in a general sense - I agree. GM skill matters. But defining GM skill is something else, something much more difficult, so I'm planting a flag in this. The ability to thin the barrier between the rules and the great unknown is a skill, or more aptly a set of skills. Different types of games force the GM to lean on different parts of this skill, and can accent strengths and hide weaknesses. If you have a good personal rapport with your players, a light system will probably work because they trust your rulings. If you have the kind of rules-knowledge to allow robust extrapolation, a more rules-driven game allows you to showcase that. The means are important, in that they impact your game, but the ultimate yardstick is how fenced in (or unguided) your players feel with the rules in your game.
1 - Because System Does Matter, Just Less Than People.
2 - Note that even old D&D has them - that is more or less what spells are.