What's the most useful policy

I voted for only Rationalism because Tradition and Liberty are virtually interchangeable. Honor and Autocracy are under-powered. Order is nice, but usually only 2 policies are taken and they are supplementary at best. Freedom and Piety are only really used in culture games and OCC(only Freedom). Rationalism is used in virtually every game except early domination games and culture games. Even then, they can be used in culture games to get a slightly slower result.

Patronage and Commerce, because they are the only two that are useful no matter what VC you're going for. Some VC's need tradition, others need liberty. Some need piety, others need Rationalism. In some, Honor is good, others not so much. Order, Freedom and Autocracy each depends on which VC you're goign for to be the most helpful.

This is one of the big areas that I hope BNW corrects. SPs should give a distinct, though not unbalanced, flavor. It's to the point that if I pick from any other policies (after Tradition), it's only because I couldn't pick from Rationalism yet. This changes if the game is cultural, or diplomatic. Still, Honor, Order, Autocracy and Commerce are never used, let alone finished.

I would have loved to enjoy Honor. Maybe if the finisher was something worth it, like melee units can move after attacking.