Hmm. My general's unit (English) is able to rout even armored spearmen units in schiltrom formation charging straight on. And, I have applied the shield fix... So, I guess, the formation is not working as intended.

Basically, in my experience, spearmen cause the biggest damage to cavalry if they manage to interrupt the charge. And... ironically, this is achieved by disrupting the spearmen formation itself: charging against charging cavalry. Loose formation works even better...