One thing I never liked about philosophy is that, for lack of a better phrase, it allowed you to make shit up. Come up with an idea, make some good arguments, there that's that. There is a minority movement seek reform. They are calling themselves experimental philosophers, and this excellent overview chronicles their efforts.
Though the article doesn't mention it, here is one problem I saw with Rawls' original position argument. John Rawls argued that, from behind a veil of ignorance, people would want to create a strong system procedural justice. Since no person would know what his lot in life would be, he'd want to guarantee equal opportuny.
Really? How did he come up with that "person"? He just made it up, of course. Or he intuited it based on his understanding of humanity.
We are a product of our culture. What if I were born into a gambling culture? Would I really want to guarantee procedural justice? Or would I vote to roll the dice. Maybe I'd get lucky, after all.
Or what if I were from a culture that believed that God preordained everything that happened. I might not even care about what system would be set up. It would not matter, after all; I would be in God's hands.
So, with Rawls, you have to pretend there is some mythical man whose decision would not be influenced by his culture. Yet.... Does that concept make sense? Vonegard may have written a book entitled "A Man Without a Country," but anyone reading his book would recognize American values.
WIth experimental philosophy, someone could actually test Rawls' theory. Behind a veil of igorance, would people really create what Rawls' say they'd create? Of course, we are still stuck with the problem of cultural bias. At least we'd know what Americans actually think. (Even then, we'd have a form of the naturalistic fallacy. Just because people would vote for procedural justice, does that make it right?)
It really is no surprise that philosophers are resisting the experimential philosophers. It's so much easier just making shit up.