From what I understand, largely from watching various campaign streams (mostly Legend/Zerkovich/MilkAndCookies), the cavalry issues run FAR deeper than a single bug. Cavalry (and a lot of flyers/flankers) are in general overcosted for their abilities; Legend makes a special point about how DE Cold One cav is a prime example of this.

Unlike their other TW games, cavalry is completely unable to provide a valid first strike option, limiting their usefulness to flank attacks which is something that can be done by infantry. They simply don't hit hard enough on frontal charge to make a visible difference, unlike in say Shogun or Empire or even Rome where following up an initial cav charge with infantry is a perfectly valid tactic (even light cavalry in Rome I are viable for frontal charges right up to lategame).

They're almost impossible to pull out of melee, unlike the cavalry from the mentioned games, meaning you need gosu korean starcraft pro APM to even think about doing classic cavalry wheeling tactics.

Anti-large is way too punishing against cavalry in general. I get the intent, but in practice it leads to some ridiculous results. Grail Knights would never crumple against goblin spearmen on the tabletop except with godlike dice rolls, but try telling that to Grom or Skarsnik.

Cavalry just don't feel anywhere near as useful or viable in WH compared to ANY of the historical Total Wars. Even in Fall of the Samurai, which is about as bullet happy as a full ratling gunner doomstack, a frontal cav charge is still an extremely dangerous experience if you take it head on. A frontal cavalry charge in WH basically ends up with the cavalry dead.