I got to say safavid makes very good points. There are at least essentially 2 schools of gamers. One that wants artificial "balance" and one that wants the game to reflect on some situation to the best it can given current limitations. Those that want balance will be satisfied by the games in the current world cyber game lineup, such as Starcraft, while those wanting more realism would probably be found playing obscure wargames or simulators.
For warband, given that it was sold on steam and gamersgate(paradox) seems to have attracted both camps in significant numbers. Steamers want their medieval team fortress, while grand strategy paradoxians are likely to have come for the supposed realism or immersion. One man's meat is another's poison, so its not productive to say which one is right.
However, that being said, chadz is firmly in the Steamer/artificial "balance" camp, so arguments for realism don't work too well in this particular mod (but not in others!).
As for couching, having no way to judge the realism, I would say it is fine. If you find yourself not being able to pull off a couch, or only making one couch attempt per round, it is usually a problem of the map. You might be in those infantry oriented maps, or archer box maps. This happens a lot in say ATS, so the problem might not be couching but the maps in rotation.
