Brettonians absolutely were the hardest hit. They're still very playable, though. The difference is that you can't just leave the peasants at home and play nothing but knights. Large units of peasants are cheap, and you can use them to keep an enemy in place so the lance formations of knights have advantageous charge avenues. While the knights still get hit first by a lot of stuff, their armor and the strength of the lances in the volume they're able to attack more than makes up for it, I think.