The reason I bring this up is to discuss a house-rule my table and I talked about when dealing with Paladins. We spoke of allowing Paladins to be of any "good" alignment not just Lawful Good, when following a good or neutral deity with good-leaning tendencies.
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Let's face it: Paladins are mortal, they have their own idiosyncrasies, they aren't perfect, and they have flaws just like any other class or person. I've always felt that they were much too restrictive by most people's standards and that a lot of people (quite a few on some forums) believe that some small acts done (when presented with basically catch-22's) constitute the falling of said paladin if he "doesn't play his alignment" perfectly.
So my question to the rest of you is how would this effect the rest of the game if I had a Paladin of Cayden Cailean who was CG at the table?
I agree with your assessment that "paladinhood" as a niche should and can be more inclusive without destroying the integrity of the game or the class concept.
Not long ago, I come up with four paladin derivative classes which expands on the stock paladin and the pathfinder antipaladin alt-class. Please feel free to try them out.
http://paizo.com/threads/rzs2pls7?Homebrew-paladin-derivatives
Here is the LG Paragon (which replaces the standard PC class), the CG Crusader, the LE Blackguard, and the CE Renegade (which replaces the alternate class from Advanced Player's Guide).
While the Paragon and Crusader are identical in some areas such as HD, BAB, and save progressions, there are certain differences (mainly law/chaos based) in their class skills, features, and spells.
Furthermore, the term "paladin" is more abstract, encompassing both the Paragon and Crusader classes, but remains synonymous with "holy warrior". Whatever does anything for or is useful to a paladin works for both the Paragon and Crusder except for law/chaos alignment differences. While lawful good items such as Holy Avengers are only for Paragons, these rules assume it's equally possible to find or create chaotic good variants for Crusaders.
The same principles apply to the "antipaladins", Blackguards and Renegades.
So a holy warrior of Cayden Cailean would probably be a Crusader rather than a Paragon. An unholy warrior of Asmodeus would be a Blackguard. Deities who are NG or NE probably have followers of both paladin or antipaladin classes, respectively.
Someone suggested there ought to be a true-neutral derivative. Deities such as Nethys and Pharasma would probably have some kind of "militant defender of balance/apathy". it's difficult to picture what such a class would look like, but I think it would differentiate itself quite strongly from the other four derivatives, since they are all based on alignment extremes.