The advantage to Philosophical isn't that you get more great people (although you do,) it's that you get them faster. This means that you get engineers more quickly after building the pyramids, which allows to you use them to instantly build another wonder faster than you normally would, which in turn allows you to more quickly generate great people, and so on. Those who claim this isn't overpowered need to attempt to create the cascade effect themselves.
I can understand the other side of the argument, though, since it is no more ridiculous than Quechuas. That doesn't mean Phi/Ind is OK, though. It means Quechuas need to be altered slightly so you can't win the game with them alone.