Right now, all I ever see from Rohan is huge spams of peasants, I haven't seen any cavalry in any games against actual Rohan players when playing online, except for the Captains of Rohan from the Assembly Point. Another thing that I haven't seen used ever, and I truly mean NEVER, are their secondary cavalry, the Rohirrim of the Eastfold, which I've tested out and I believe to be less effective than normal Rohirrim. Here is another idea from me to counter pikes: Make it so that Rohirrim of the Eastfold do no trample enemies, therefore not dealing crush damage or receiving crush revenge damage from pikes. Additionally, make their blades deal extra damage to units without heavy armor when they don't have forged blades, and deal extra damage to units with heavy armor when they do have forged blades, and finally they should deal an additional 40% damage to pikes overall than other Rohan cavalry.
This would take what truly is a useless unit, even more so than peasants in late game, that nobody ever uses, and make them an effective pike counter. It would do it without making them OP because they can't crush units and aren't as good as normal Rohirrim against swordsmen/archers, while also not straying away from the factions lore.