See, that's the thing. People forget that the reason for the code wasn't for rp. It was for mechanical balance. Remove the balance issues and you remove the need for a code.
I disagree. Following a code is not hard. So if every Paladin just follows their code they get to be more powerful? Following a code is a roleplaying hook. Just like Clerics follow the dictates of their deity.
Putting in world flavor restrictions on yourself is just plain roleplaying. It's not mechanical nor should it be. And I'm not arguing what was done in the past pro or con about balancing the classes. I'm saying that today we should not balance classes with roleplay restrictions. Roleplay restrictions are there to make playing the class more fun and more flavorful. If you don't enjoy it then don't play that class. Some people actually do enjoy it.
I think that's one legitimate way to go, yes. It requires rethinking "clerics" pretty heavily. 2nd ed AD&D did a bit of this. I personally think it puts a lot of pressure on the coherence of the paladin class, though, because once you go polytheist and, from the point of view of the game system, abandon the view that LG is the objectively best alignment, it becomes rather mysterious why only one set of gods has special champions.
The other way of going is the 4e way, which embraces the distinction between clerics and paladins as primarily mechanical (and adds invokers into the mix) - so you get STR clerics and paladins, WIS melee clerics, CHA paladins who are mostly melee but with a bit of spell-casting, then WIS caster clerics and invokers filling the role of "white wizards".
I think it's a bit of an unstable combo to try and go both ways at once.
It will be interesting to see what oaths are available. I think an Oath of Freedom would be great, even if it tends towards the more chaotic end of the scale. The blackguards could be represented by the Oath of Betrayal, which I could see errant paladins of other oaths switching to if they can't abide by their original oath (I'd have the player making this choice, rather than delivering it from on high).

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.