The whole idea is that because cav costs more to play in upkeep, it will keep the cav population lower. But with the amount of gold you can rake in from one heirloom point, you can afford to ride not just cav, but heavy, plated cav, for generations to come off of it.
The other big problem is the hitboxes. The horses head is a ridiculous small area of snout, and if the rider has a shield and can hold down the right mouse button, especially if they are Heavy cav, they can ride away from most rearing situations fine. Stab into the horses lower side? You hit a shield. Do an overhead from behind when the rider turns slightly? Hit his shield. Try to swing through the body of the horse just a little too high? You hit the shield. It's really bogus how a medium-high shield skill on horseback can protect you from what should be a lot of damage to your mount. Add to this the fact that ranged damage on ponies are pretty wimpy now, and you're going to see a massive influx of cav, as we are.
I mean I saw a Destrier riding around with 2-3 arrows, 2 throwing lances in it's body, and watched it get hit at least once in melee. That is totally redonkulous. High tier throwing should be one of the natural foot counters to cavalry. Pikes and pokey things should be the other, and they are to an extent, but fall very, very flat on heavy cav.
To make matters worse, at least on NA 1, you'll often see one team get almost ALL the cav balanced to their side, and it's really lame. The natural counter to heavy cav at the moment is light-medium cav, but what can you really do when they're all balanced to one team?
So my two-cents on solutions: reinstate ranged damage to horse bodies, alter horse head hitbox to encompass actual head instead of just the tip, and do something to separate the horses body from a shield forcefield. Lastly, work skills like PS, riding, PD, PT more into balance if that's at all possible. Phantom edit.