On the settler policy, in addition to the +50% point noted above (doesn't mean "double settlers"), to get the benefit of that policy you have to build your settlers in your capital. Your capital should have the best production, so perhaps that is OK, but there are often so many other things you would also need/like to build in your capital.
I've found that wanting to utilize the benefits of that policy can skew what would otherwise be my capital-build preferences, while that is not the case with Tradition, where I might pump out settlers from a couple of expos while letting my capital build, e.g., National College (or whatever). You can certainly do that with Liberty as well, but psychologically it can feel like you are playing sub-optimally by not taking advantage of one of Liberty's most notable policies. I think that psychology is also what leads many Liberty players to defer building their first settler until they get their free settler, even though it may be quite beneficial to pump out (perhaps forest-chop) your first settler earlier.
On Redaxe's religion point, yes, you can use other tools (like religious beliefs) to mimic some of Tradition's benefits, but you could also take those same religious beliefs with Tradition and enjoy a "super-Tradition" game. (Just like with the Aztecs, you can take the Honor opener for super-culture from barbarian kills, or you can skip Honor and still get culture from kills.) Not sure that proves much either way.
I've found that wanting to utilize the benefits of that policy can skew what would otherwise be my capital-build preferences, while that is not the case with Tradition, where I might pump out settlers from a couple of expos while letting my capital build, e.g., National College (or whatever). You can certainly do that with Liberty as well, but psychologically it can feel like you are playing sub-optimally by not taking advantage of one of Liberty's most notable policies. I think that psychology is also what leads many Liberty players to defer building their first settler until they get their free settler, even though it may be quite beneficial to pump out (perhaps forest-chop) your first settler earlier.
On Redaxe's religion point, yes, you can use other tools (like religious beliefs) to mimic some of Tradition's benefits, but you could also take those same religious beliefs with Tradition and enjoy a "super-Tradition" game. (Just like with the Aztecs, you can take the Honor opener for super-culture from barbarian kills, or you can skip Honor and still get culture from kills.) Not sure that proves much either way.