In RTW, it was normally sufficient to have a long line of infantry with calvalry on either side and "hug" the enemy. The major difference I find in M2TW is that the enemy calvalry are much more likely to break through my line of infantry and are more willing to retreat and reform behind my line. In RTW, those calvary rarely broke through and even when they did, they would fight to death in melee whether they're winning or hopelessly outnumbered.