WARNING GEEKDOM POST BELOW...DO NOT READ UNLESS YOU WANT TO BE OVERWHELMED WITH GEEKITUDE
Matt Forbeck posted a link to an excellent article by Greg Stafford discussing game design decisions in roleplaying game design. In the article, Stafford discusses two underlying philosophies regarding what to include or leave out in a specific game's mechanics. To quote:
A genera game player wishes to imaginatively experience a limited and specific setting, within its own context and rules. Basic Pendragon is this kind of setting. It is about knights in a pseudo-medieval setting that includes the fantasy and legend that is (more or less) appropriate to that setting.
A generic game may use a specific genera as a basis, but the players want to expand it with the modern experience of open, freewheeling experimentation. Not just knights, but druids and wizards and thieves and ninjas in a King Arthur-like setting. Not just traditional knights, but women knights, Beowulf-era warriors, and Sigurd and Theoderic and El Cid too. Not just native British folklore, but kobolds and nagas and deep ones too.
His article is the beginning to a wonderful discussion, and one at the core of game design. When Matt Forbeck designed the Brave New World game system (based on Greg Gorden and Shane Lacy Hensley's system for Deadlands ) he had to decide whether to make his game a generic superhero game with the ability to capture all superhero types or whether he wanted to limit the types of heroes and the scope of powers to fit the genera his fictional narrative provided. He chose the latter. Because Forbeck's fictional history of the United States was one in which Alphas, or almost limitlessly powered superheroes, no longer existed. The only "supers" who remained in Brave New World were the lesser powered Deltas who primarily fit into easily defined archtypes.
Given the high level of competition in superhero RPGs, Forbeck's decision was a brave one and a necessary one. In the end, Forbeck produced an internally consistant game that was largely free of the "power creep" often associated with more generic settings.
But what does this have to do with Fantasy games, and the Paladin in particular? One of the big reasons people play Fantasy roleplaying games (big F because I am referring to the genre and not the game type) is to, for a brief moment, imagine and act as if they are one of their favorite characters from fantasy literature.
Games like Dungeons and Dragons allow players from a broad array of fantasy traditions to play the same game with only slight limitations. If you want to be Aragorn you can. If you want to be Belgarath you can. If you want to be Fafhrd and the Grey Mauser you can. The Dungeons and Dragons system is fairly generic and has become more so under the design influences of Monte Cook and Sean K. Reynolds. Certainly more so than Pendragon. But Dungeons and Dragons isn't a completely generic fantasy RPG.
In fact, Dungeons and Dragons has some very specific limitations resulting from the interpretation of fantasy that its initial game designers had. Gary Gygax's vision of fantasy was one inspired by H.P. Lovecraft, Clark Ashton Smith, Jack Vance, Tolkien, Michael Moorcock, Fritz Lieber, and Robert E. Howard (among a few others). As a result, the game does a wonderful job in simulating the source material. The magic system is rooted in a "Vancian" system heavily influenced by the Dying Earth stories of Jack Vance. The thieve's abilities, including the ability to read/use magic scrolls, is heavily influenced by Lieber's Fafhrd and Grey Mauser. Rangers come from Tolkien. The strict alignment system comes from Moorcock (among others). And the dreaded Temple of the Frog comes from Lovecraft, Smith, and Howard (Tsathoqqua arguably makes an appearance in Howard's Scarlet Citadel). The combination of influences lead to an interesting kaleidoscope rules set where Vancian magicians battled Hyperborian warriors.
This made for an inspirational and cutting edge game, one that spawned an entirely new game type. But fans soon found that they might need other rules sets if they wanted to play their vision of fantasy. Monte Cook and Sean K. Reynolds are among those for whom the kaleidoscope of earlier versions of Dungeons and Dragons were insufficient and some of their opinions can be seen in the current rules of the game. I say some because there are a couple of choices that Cook and Reynolds were pressured into by playtesters that Cook and Reynolds are less than satisfied with. One of these choices is the limiting of the Paladin class to Lawful Good alignment. The Paladin, you see, is a chosen defender/crusader for a god and couldn't an evil or not lawful and good god have defender/crusader's?
The answer is a simple one...yes and no. In a completely generic fantasy simulation, ti would certainly be reasonable, but in one where each character class comes from a different inspiration it isn't. The Paladin, like the Thief, in Dungeons and Dragons have very particular archtypes it is modelling. Why do all Thieve's have to worry about "thieve's guilds" in D&D? Because they did in Lieber. Why are all Paladins lawful good? Because Lancelot and Galahad are. The Paladin may exist in a roleplaying game with polytheistic pantheons in abundance, but it was inspired by mythology from a monotheistic society. Genre convention is the reason for the choice. It may not be a reason that satisfies Cook and Reynolds, because in many ways it is an arbitrary choice, but it is a creation of the understanding behind the creation of the class.
J. Eric Holmes, author of Dungeons and Dragons first basic set, gives another reason that Gygax may have which is behind the requirement. To quote his book on Fantasy Role Playing Games:
I don't mean to imply that the designers of games set out to teach us little moral lessons about everyday life -- except Gygax. In the D&D world fighters can do no magic, but magicians are so weak that they need to be protected by fighters. Clerics can heal wounds and do a lot of fighting but are no good at long distance offensives because they can not shoot arrows or throw offensive spells. The constraints of the rules practically dictate cooperation and mutual respect for the talents and weaknesses of each class, and I find it hard to believe that Gygax was not fully conscious of the principle when he wrote them.
Gygax calls this "play balance" and insists that it is not good for one character to grow too powerful with respect to the others. It is just this principle that some designers of other games have objected to and tried to write out of their own rules.
From a "moral education" standpoint, it makes sense to give additional powers and abilities to players willing to make sacrifices. If you create a game where some mechanics and goals feed "greedy" behavior, a class that accepts limits but gets benefits in return is an educational tool.
This is not to say that more generic games are less moral, that depends on the players involved. But what is certain is that in my experience those who want to play the Paladin with all the abilities and none of the restrictions have yet to give me a compelling argument not based on self-interest. At least within the context of D&D, in the campaigns I run. It is easier to defend the Paladin if you limit the Pantheon(s) available to the players. Easier still if your "universe" is monotheistic. Mine isn't, I play in Eberron, but I limit Paladins to the Silver Flame.