what doesn't imo really pay of are high vetted units, because artillery will tear them to pieces before they will even be able to engage into the battle. maybe for cavalry some vetting would make a bit of sense, but overall i prefer just numbers over quality so enemy arty fire doesn't hurt that much.
Vets sux if you use too many of them in a single battle (sometimes I do just to make sure I level up a lot).
But some upgrades are soooooooo powerful that you will certainly lose against some high-level general who unlocked things like improved range, or some special abilities of a particular unit.
My bet would be to have one veteran unit out of ten maximum to still collect xp without being overwhelmed.
When you are dealing with light infantry with 175 range and/or elite infantry with 150 range + deadly accuracy, you have a serious issue on your hand and if you cant deal with them they will butcher you.
When you have them on your side, you just know that if you protect them well enough, you will pulverize any units in front of them.
Now to stay in topic, I have a tactic I love to use everytime I have a good number of cavalry units under my command:
Trying to attack the rear or the flank of the ennemy infantry with your cavalry is easier said than done... The opponent (if they arent stupid) will either put pikes near them or try to intercept them with their own cavalry.
What I often do is use my cavalry sparingly at the beginning of a battle, and only send them when I know I have the upper hand.
Now when the infantry/samurai clashes and they are locked into firing positions and/or moving/not being able to defend themselves fast enough, I often make a mass charge of my cavalry around their flank NOT EVEN TRYING (on purpose) to conceil my intent, but here is the thing: they will undoubtedly intercept it with whatever pike/cav they have and think they are smart and I cant react fast enough.... but now you position ONE of your cavalry unit and make it charges so it attacks and blocks every intercepting squads the opponent sent you, and you use your remaining force with as much freedom and speed as you can and freely charge their flank or even their rear.
This cant work if the main ranged arent locked in battle or they have infantry in reserve ready to repel any angle of attack, and cant work too if they have more than ONE group of intercepting force (they often send them in a pack so its pretty rare to have more than one).
Cavalry are for me the battles changers of shogun 2... infantry is just here to try to have the first shot, making some casualties and focusing squads to lower morale for a rout and making the battlefield more "stable", artillery is useful only when focusing powerful units or particular spot you want to rout (and even then)... but Cavs are, with their speed, the only way to make easy surprises and attack with a powerful angle.
Too bad there isnt much cav units.
