Ok, only if all horses get +20% maneuver, HP and speed and +100% charge.
Tbh you can't just nerf cav based on higher (and I'd even say it's more volatile rather than actually high) battle mode k/d. Cav doesn't work well against people playing together with voice conf, even not competitively. And if you look at it closely you'll see when cav top the scoreboards, it's usually because they were able to kill the weakest, not the important targets.
Furthermore, doing this would only cause more jousting/great lance people to show up. And I can guarantee you don't want that to happen.