Pikes just aren't that effective against cavalry right now, which is a feat considering how wonky the cav AI (or more accurately all AI decision making in regards to melee weapon length and footwork) has been since 1.8.0. Of course, the current AI issues also affect the infantry when they brace, but assuming that the AI will be fixed, the pikes need to be longer than 300 length to be effective against heavy cav.
Another issue that needs fixing is units like the vlandian sergeant and battanian oathsworn which have braceable spears failing to brace when they also wield a shield. Either make them put their shield on their back, or make spears braceable with a shield. Interestingly, I have seen dismounted cataphracts putting their shield on back to spear brace against me when I was mounted. I'm 99% sure that the reason for this was their spear being 2 handed only, so there is an easy solution of making the braceable spears in loadouts 2 handed only.
Another issue that needs fixing is units like the vlandian sergeant and battanian oathsworn which have braceable spears failing to brace when they also wield a shield. Either make them put their shield on their back, or make spears braceable with a shield. Interestingly, I have seen dismounted cataphracts putting their shield on back to spear brace against me when I was mounted. I'm 99% sure that the reason for this was their spear being 2 handed only, so there is an easy solution of making the braceable spears in loadouts 2 handed only.