If a player brought you an excellent concept for a plain Good Paladin, a truly excellent concept, would you reject it for the alignment at the top?
I am going to answer this even if it was not addressed to me. Depending on the concept I would be willing to make an exception and help design the class to fit though I would most likely give it another name.
But then I have done the same with a player who wanted a lawful good rogue he wanted a loyal to the land spy who believed in the greater good.
Dragon had some excellent paladin classes for other alignments in it.
There is nothing stopping anyone from changing things to fit what they want DMs and players have been doing this as long as the game has been around.