paladins
Here are my experiences. I played an AD&D paladin, a 3.0 paladin, and a 4.0 paladin. I liked the 4.0 the least, because at the beginning, str-paladins sucked in terms of support. Now, had they had the divine power options from the start, that would have changed my opinion of them. But AD&D paladin restrictions, where you must atone, was kind of annoying, and kind of cool, at different times. It forced immature players to have real consequences to their in-game selfishness for magic items or cowardice (let the other guy die while I run away). Having the DM have the power to say, your god disapproves, you no longer feel holy. (you are now a fighter until you atone, or perhaps permanently)
So on the one hand, it's good, and on the other, if we have Anti-Paladins who are C-E, or L-E, why not a somewhat-anti-paladin who's fighting for good in a land where the laws are used for evil (e.g. well...any country, in fact). You could make a strong case that being CG is more good than NG, in such a society. Depending on how utterly corrupt and status-quo promoting the legal system is. Lawful inevitably (or at least often) means the paladin must do what his patron or king says, even if that King has been corrupted and whose morals are themselves lacking, or perhaps under the compulsion of some evil demons. This happened in one of our games. So you had to use your judgment, is this order to kill every rebel a just one? Remember, you cannot disobey your liege or the tenets of your faith, even though they may be "evil". I always saw Lawful Good as Lawful > Good in terms of precedence, because "I was just following orders" is EXACTLY what you must do, all the time, or you lost your paladin-hood. You can question orders, and feel at peace, but your connection will be severed and powers lost. It says it in black and white in the penalties for disobedience described in the class.
So, in this modern era of shades-of-grey vs black-n-white, I'd say, you should follow the alignment of your god, but have very specific orders and edicts for each paladinhood, and if you don't follow those, then you pay the price. No deviation allowed. Knowing the Path is not the same as Walking the Path(tm). You are a paragon of your faith, beliefs, moral code, set out at the beginning of your training, by a religious order or priesthood, or perhaps just a kingdom or a god directly. Also, your devotion to an alignment should be somewhat up-front. If you are a champion of chaotic ideals, you should be rewarded for increasing chaos, and penalized for NOT knocking over that fruitcart or causing a disruption to those guards who are harrassing that kid, over there. There are different kinds of champions, but their alignment and moral code should be rigidly adhered to.
That said, I see nothing wrong with having the PHB Core paladin being LG only, then adding the other alignments in subsequent books, like surely the anti-paladin will be. This is probably what will happen, I bet you any money. (ok, 1 cp)