... Is that many players don't want to play paladins. They just want the powers.
This is the conclusion I've come to after reading many, many discussions about paladins. Whether you think of paladins as the flower of knighthood, as I do, or the servant and epitome of some god on earth, as many modern fantasy games do, the point of the paladin class is not the powers. It's the the paladin's code, the restrictions on behavior. I've written before about what I think the paladin's code should be, so I won't go into that. The point I'm focusing on here is that there has to be a code, and it really shouldn't be one the player creates. If you want to make up your own code, pick a class like Fighter that has no code and add your own code. If you want powers that come from some god, pick a spell caster class and say your powers come from some god, although even there, there should be some expectation of being judged by your god.
And you shall be judged. None of this "I'll do whatever I want, then retcon my actions as being in line with my code." That's bullshit. If you want to do something like that, play another class and say, "I have a code," but don't say what it is. Make it up as you go along. The point of a class that has strict behavior standards is to challenge yourself to see if you can meet those standards. And the point of taking a moral code is to have your moral code challenged. Saying "I want to be a paladin" is you challenging the GM to test your morality. You're saying "this is what I want my personal story to be about.
And don't get me started about the "Lawful Good, not Lawful Stupid" argument. Critics who bring up the Lawful Stupid charge always provide examples where what's expedient is in direct conflict with most strict moral codes. What's expedient is often not what's good, maybe not even what's Lawful. Again, there are already classes to play if you want to base all your decisions on expediency. Choosing the paladin means choosing to not always do what's in your personal self-interest. You have to choose, sometimes, and know that if you do what is expedient instead of what is right, you may lose your righteous powers,. If you don't want the GM to ever, ever take away or reduce your powers, then the paladin is not for you. Move along.