Stay Classy is a series of articles covering the immense topic of classes, backgrounds, professions, etc, both in and out of "sneak". You should start with (1).
This time I'm going to talk about the open class model. I'm going to define "open class model" in the following way: "any class system in which the player chooses a class at the beginning but is not restrained by it throughout the game". Some good examples of open class model games are (early) Star Wars Galaxies and Dungeon Crawl Stone Soup. In both games, players pick their starting 'class' (profession and background, respectively) which grants the player basic equipment and a few useful skills. Beyond the starting point players are allowed to follow on the logical 'path' that the game starts them on or go in a completely different direction. For example, a player in Star Wars Galaxies may have started out as a Marksman but end up focusing entirely on the Artisan skill set.
The open class model is significantly less common than the limited class model. It seems likely that this is true because of the reason the limited class model is popular: simplicity. The open class model is much more challenging to design and maintain. Players can create hundreds if not thousands of different combinations in most open class model games, which is a serious pain in the ass for even the most skilled designer. This can also be rather perplexing as a player: much the same way a player can pick the wrong class in a limited class game, a player can also "build" their character the wrong way and not end up enjoying them in an open class model. However, in both of the cited games, the designers found fairly reasonable solutions to the player's problem.
In Star Wars Galaxies, players had the ability to reclaim their invested skill points and re-distribute them as they please, at least so long as they earned the appropriate experience. In Dungeon Crawl Stone Soup experience is more-or-less unlimited after a certain point, so flawed skill choices are only a serious setback early in the game or during a so-called "challenge" play through. While both of these solutions are valid, they show that open class models require either fine-tuned balance or some kind of "cheesy" system to avoid the player problem.
From the perspective of Star Wars Galaxies, it doesn't really make sense that a master chef forgets how to cook in order to become a master sniper and martial artist. From the perspective of Dungeon Crawl Stone Soup, it makes equally little sense that some single person is so outstanding that they can master every skill in the game (given enough time, willpower, and sheer desire). Still as a designer and a gamer, I have to applaud both games for at least trying out their solutions instead of just leaving the disgruntled player in the dust.
Personally, I tend to prefer the open class model, though I do recognize its downfalls. It is quite likely that "sneak" will take the less traveled road and end up squarely as an "open class model" game. This brings me to my closing statement: the next installation of Stay Classy will explore the possibilities of classes in "sneak" and how I intend to handle them.
You can continue this series of articles here (3).