I'd like to meet a man who can shoot accurately on a moving horse. I think they should be able to shoot on horseback, but significantly worse when moving. While off of the horse, they should be much more accurate, but it should really come down to the playstyles of the group. Perhaps some would want to quickly flank around the enemy, dismount, get excellent shots off, and then upon getting charged, mount and disperse. Others may prefer being a shock unit rather than a skirmish unit, by picking out a blobbed, unprepared target, getting in their proximity, volleying, and then charging with sabers, which is much harder to pull off, but should still be allowed. This way, cavalry regiments that can successfully pull off both styles of fighting, and perhaps even more, will have extreme advantage on the field.
As far as fairness in events go, I'd say that if a cavalry regiment runs up, volleys, and doesn't charge, that should be punishable. What's really unfair is letting cavalry get fairly accurate, but very up close shots, but then letting them gallop away quickly.
The big solution I see though, to nerfing the cavalry, is slowing the horses a little. This way they'll be less willing to take risks, because it would become harder to run up to infantry, shoot on horseback at a halt, and run away the second someone gets near. Just a slight change in their speed could do the trick.
War isn't fair. Don't know why people keep trying to change that. I have a lot of respect for Hinkel for making this game as accurate as he can.
As far as Cavalry tactics, that should be up to their commander, not their enemies. Dictating combat takes away from potential cunning and creativeness to achieve victory. Only thing I can see being moderated is the percentage of Cavalry on the battlefield, and our admins seem to keep that in check.
"It is unfortunate when final decisions are made by chieftains headquartered miles away from the front, where they can only guess at conditions and potentialities known only to the captain of the battlefield."
- Atilla the Hun