Well, ther is a 2 handers bug, but in 1.03 it is fixed, to sam point at least. Alltough many of the units perform below their oficial stats, they are of some use. The problem is that the diferent units have diferent level of improvemt. But basicly try not use much of the 2 handers, exept maybe Janichary heavy infantry and tabarbareyars (or somthing like that). They work fine. The problem with 2 handed units is in their slow animation, and slow attack speed. Now in Kingdoms (but not in the grand campain) this is fixed, allmost complitly. You can use the retrofit mod to fix your crand campain, but br awere that this will make your cavalery units to the sice of 30, not 40.
By the way you DON'T need dismounted english knights anyway, you have one of the best heavy infantry units in the game- armored swordsmen.