Really depends on your Civ. Poland, Rome, The Maya, and other wide Civs can benefit from Liberty, and even settle enough cities late to take liberty if they are planning on a early Deity war (Pre-Renaissance is early for war on Deity imo). Most warmongers (Ashurbanipal, Shaka, Sweden) really benefit from Tradition or a Tradition/Honor split.
You cannot prepare for war on Deity and REX, at least not if you want to be in the medieval before someone picks an ideology.
Liberty can be good with as few as 4 cities due to the speed at which you can get them out, but unless I want to go heavy religious or spam a UB, on Continents or just vs Deity AI in general Tradition is a lot safer, and if you are going to war it is the only choice.