Out of sheer curiosity, and as a complete aside to this entire conversation, what is cav's weakness?
They have to sacrifice some Strength or Agility for the riding points (unless they substitute athletics for riding).
They have to pay high repair costs for the horse (and lance, if they use one).
They are outreached by longer polearms and occasionally, greatswords.
The horse can be reared by polearms over 140 length, leaving the horse open to 2 or 3 easy hits. Even more if caught in a group.
They are highly susceptible to ranged. Large, easy to lead due to predictable movement, etc.
If the horse dies, the rider can be hit around 2 or 3 times while getting up off the ground (unless he sinks into the ground or he teleports somewhere, damn bug).
Could probably think of more, too lazy to at the moment.