Oda is insanely strong. Their traditions right off the bat are +10% Morale and +10% Infantry Combat Ability. This stacks with +10% Morale from Shinto religion and +10% Morale and +10% Infantry Combat Ability from Daimyo government. Let me rephrase that - Oda has +30% morale and +20% Infantry Combat ability from day one, without any ideas selected. This lets them stackwipe pretty much any army with ease. Take a couple of loans and go over your force limit by a few troops and every other daimyo will melt like butter. it's so ridiculous that after the first couple of initial wars, you can just declare war on everybody in Japan one after another and ignore coalitions, and have Japan unified within the lifetime of your first ruler. Keep in mind this is an OPM subject that starts with a force limit of 4.
Then you get into their ideas: Their first idea is Goods Produced, one of the best economic modifiers in the game. Their second idea is 10% CCR and -10% Province Warscore Cost. Their other ideas give Land Leader Shock, Fire, and Siege (!), as well as a straight boost to Land Fire Damage and 20% Manpower modifier/-5% tech cost for good measure. Basically every one of their ideas is geared for war, and the ones that aren't strictly combat-oriented are still helpful. They have no pointless naval ideas, no wasted slots that might as well be empty (10% stab cost mod, etc.). Just great ideas for smashing everything around you.
Of course other countries have ideas/governments that are good in other ways, but Oda really just stands out to me as amazingly good purely on the merit of its idea set. Especially since it's not even a formable like Persia, Italy, or Yuan.