Bill Campbell wrote an article on his blog, World of Discourse, about his belief that skill-based and class-based systems only differ superficially. It’s definitely worth reading—this post started as a comment on that article, but rapidly grew into an article worth posting here.
I've been thinking a lot about class- vs. skill-based systems. I disagree that the distinction is superficial. The two systems do share the same basic building blocks: powers and abilities. They each do define boundaries on how a character can interact with the world and how effective it will be. But these two facts do not mean that the two systems are indistinct. They are appreciably different organizational schemes--different ways of character planning.
I may go as far as to say that this is a false dichotomy. There is no canonical skill-based system, and all skill-based systems naturally move towards classification (and being accused of being a disguised class-based system). Whatever ties different skills together and allows them to more easily advance in parallel becomes a classification. For example, if I want to be an expert swordsman, I’m going to want to have skills that allow me to dodge and parry my enemies frequently as well as do a lot of DPS. I have strength and dexterity as my main statistics. Naturally I’m pushed towards certain types of skills by my decision. These common sense patterns of skill bundling are inherent in what we’re trying to do when we play MMORPGs. It seems like the distinction is “does the system have explicit classes?” If it does, it’s class-based. If not, it’s “skill-based.” When someone says “class-based”, you immediately know what he’s talking about: a game whose power advancement is similar to Dungeons and Dragons in its fundamental concepts. When someone says “skill-based”, he’s not giving you much information, aside from the fact that the game may not be close to D&D.
In short, skill-based systems are defined by a lack of explicit, forced ability bundling, but this doesn’t actually tell you anything about the advancement system!
And I haven’t even mentioned that there are also class-skill hybrids: the job system in Final Fantasy Tactics is an example.
But why is the distinction between class-based and non-class-based power advancement not superficial?
In a class-based system, character planning is significantly simplified. Most of it is done by the game designers. The number of viable builds per class is usually no more than three, most often two or one. There are often more classes then there are roles to play in the game, and a character that only can fulfill one role is boring to play. There ends up being a lot of ability duplication in the game by necessity. Balancing this duplication becomes a primary concern of designers.
When you remove this pre-bundling of abilities, players now can have a much stronger role in the shaping of their character’s power. There are important decisions to be made throughout the character’s career and the player must make them with intelligence in order to have a strong character. Although the developers still need to keep many different abilities useful, shifting the balance responsibility of power bundling from the developer to the player vastly changes the way the game is played—the player has more agency in their character’s progression than the developer does (within the rules of the game system), and I believe this is very important to the design of the system. it’s a far-reaching and meaningful difference.