the Doing, Having, Acting post about how classes aren't about what your character can do, but what your character chooses to do. This is a restatement of something I've harped about before, about how classes should be archetypes rather than professions or skill packages; each class offers an answer to the question "How do I solve problems?"
But there's more to it than just that. After all, pretty much everything a character does is what the character chooses to do, right? Yes, on an individual level. But I'm talking about an aggregate of many choices over time. When a player chooses "fighting" as their character's go-to solution to problems, thus choosing to play a Fighter, that's a signal of what the character is likely to be doing. But it doesn't mean that's all the character can do, or what the character will definitely be doing the most of. It's not even necessarily a sign of what the player wants to see in the game, as some RPG design theories promote.
The character's improved combat ability is really a carrot, dangling in front of the player as a bait to solve any problem that comes up by direct force. But the player doesn't have to take the bait; the character should be allowed to choose any action that's theoretically possible, without restrictions other than those present in the immediate environment. The kind of play that appeals to me revolves around these choices, where the player can take the easy way out -- the carrot -- or take an option that appears more interesting.
Now, you can theoretically play that way in any RPG system. However, there's been a trend towards overdesign in RPGs for some time, where the designer attempts to show or force the player to play a given character in a given way. Games designed this way assume that what players do is build characters that fit a given role in the party and then play completely in accordance with that role; good play is defined as being able to make the best character build choices and then use your character in the most optimal manner. That goal is completely antithetical to the goal I described above; choosing not to act in accordance with "what your character does" is considered non-optimal and will get you a good shouting-at, if you are playing with the wrong people.
This is why my focus has been on defining classes as archetypes and stripping down their abilities to just two or three, to reduce the complexity and more importantly the emphasis on character builds. A good class, in my opinion, defines as little about your character as possible, so that the real character building will take place as a result of choices you make while playing.