KidSnide
Adventurer
On the other hand, if the paladin is really a distinct class, then I expect the code to do more than be a bit of character flavor. I expect it to be the hinge around which the synergy of fighter and cleric is woven into something notably different than a fighter/cleric multiclass of the same level. That means it has to interact with the fighter-type and cleric-type abilities mechanically in some ways. (Simple example off the top of my head. When a paladin turns undead or demons, it works the same way as it does for a cleric as far as odds, numbers, power, etc. However, the effects are somewhat different. Perhaps the cleric is more focused on causing such creatures to cower and then flee and then be "banished", where the paladin causes them to weaken and eventually turn to dust.)
I would hope/expect the code to have a mechanical effect, and I think the Essentials version of the paladin goes in this direction. As a minimal example, I would hope that paladins get some kind of "smite" class ability that is only usable on enemies to the paladin's code/deity. That's not much of a restriction since a typical paladin will be fighting evil 90%+ of the time, but it's a good character restriction in that some of the paladin's powers won't help in morally ambiguous situations. I likewise think it would be cool if paladin's tended to get a defensive "heal self" or "throw off effect" power that only worked while consistent with code. (The details of these powers could depend on the code chosen.) Either way, this (along with detect evil and maybe a horse) is the sort of thing I see as unique to a paladin.
The synergy with other classes comes in spell lists and shared class abilities. To the extent paladins get class abilities that involve spell casting (or maybe specific spells appropriate to the code), I would like to see those spells mostly come off the cleric list. Likewise, they may get some class abilities in common with fighters (weapon use? maybe number of attacks?). If a paladin wants to get more fighter-y or more cleric-y, they could take a theme that gives them combat maneuvers or maybe a theme that provides a cleric domain.
Of course, this is all shot-in-the-dark speculation. We'll know more when we see a paladin playtest.
-KS