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).
Oath of Freedom paladin, CG would be a character I'd love to play, but it would end up being similar to a slavery-hating, law-breaking barbarian-rogue in temperament, if not abilities which would be more magic based. But those are still interesting mechanical and philosophical differences even among CG characters, which I like.
However the Oaths need repercussions for acting contrary to your Oath. Maybe a temporary disconnection to the magical powers granted for the Oath itself, would be fine. It's not so much a power balancing mechanic as a roleplay enhancing one, and I just don't believe in people taking Oaths with their fingers crossed behind their backs and still getting rewarded for that, and treated like they are still following the path. I would even go so far as to say you can't progress along the Oath. There should be a way to switch your Oath with a ritual or a lengthy change of religion. People do it that quite a bit, I don't see why D&D gods or magic need their followers to keep following them until they die, even over their objections. Others might jealously seek vengeance. Like if you betray a vow and go from paladin to anti-paladin, that's more serious than going from a champion of justice to a champion of freedom. I think changing along the good-evil axis is worse than the law-chaos one.
People who are chaotic often do have an internal compass or vow or code or mission, it just isn't rigid, or dogmatic in the same way. A rogue could take a vow of lawbreaking, and say he needs to steal something every day, and as a paragon of that type of Oath, gain appropriate abilities that assist them in achieving that objective. Lots of interesting characters are possible, and they all depend on Oaths being taken and not broken. Take your Oath seriously, no matter what it may be, it needn't be alignment based but a LG paladin of justice should exist, and lose his powers (even temporarily) if he breaks his Oath.
They need to add optional rules for that, to make the entire purpose of the class make sense again. Right now the class makes no sense, because Oaths are often merely treated as fluff to gain tha goodiez you want for your murder hobo du jour. Oaths are not fluff.