Help me enjoy MTW!

[Haccapelite]

From your description it seems that you really don't need any kind of in depth-guidance on how to fight battles, since you use all the tactics that should win you a battle quite easily. (flanking etc) And I also believe that you know the rock-paper-scissors mechanics of this game, so the problem here isn't your lack of knowledge. I use all the same tactics that you have mentioned in your post, and my standard west-european army looks pretty same as you, but I could give you some hints that may help, or may not, but anyway..

I think some of your high casualities might be explained by the fact that with a large army, it is hard, if not impossible, to keep an eye on every single unit of your army at once. But thank god, or CA, there is a pause-button! I confess that I use the pause-button very much, and at least for me it is absolutely essential when I'm using units that require lots of micro management, eg. horse archers and such.

You said that sometimes a single enemy general can eat huge numbers of your units and rout your men, well, that isn't actually that rare. The general unit can have a huge valour thanks to the glitch that counts every valour-boosting virtue of the generals unit twice when it enters the battle. So it isn't rare to see princes and kings with over 10 valour on the battlefield, and a unit with such a huge valour has so high attack, morale and defence that they can survive alone for very long. (I think that morale is the most important factor here as it keeps the unit fighting and enables it to sustain large casualities without routing, and a unit that has 10 valour has 20 more morale than a similar unit with no valour.) And when a unit is reduced to just one man, it gains more valour very fast, since it doesn't have to kill so many units to get even more valour.

You should remember that cavalry is mostly used as a pure shock troop, to break wawering enemies and deal the final blow to them and turn the battle to your favor. They are not meant to be used in prolonged melee, and if you have the option you should just pin the enemy with some spears or such and then charge its rear with cavalry, let them fight just for a while, then back off with the cavalry, repeat the charge again, and continue this for as long as it is necessary. I don't think i have seen any non-general unit survive more than two charges to their rear, since the casualities and morale penalty that follow a rear charge are so huge.

Also, I don't think there is such a thing in this game as a default army that would work against any foe. You should always adapt your armies to match the enemy you are facing as well as possible: If you are fighting someone with huge numbers of horse archers, don't attack with an army mostly consisting of footmen, intsead train lots of fast light cavalry, if your enemy has lots of infantry and almos no cavalry, get much swordsmen and some heavy cavalry, etc etc.

There is one more thing: Fight. Try to get to fights in your campaings as much as you can, if nobody attacks you, just attack them and fight every single fight, small or large, yourself. Some of these things just can't be taught but you have to try them yourself.

I really can't think of any more things, I hope at least some of these are useful.