I think alot of people forget that for the most part, all around the world for a long period of time, Cavalry WAS a support/shock role, if it wanted to be effective against most decent armies that is, there was a very small time period in history where Heavy Cavalry could just charge mindlessly head on into the enemy ranks and win, which is why tactics like the Hammer and Anvil exist.
Often the Cavalry from both armies would engage in attempt to beat the enemies cavalry and rout them from the field, allowing them to flank the enemies already engaged infantry, charge and cause a mass rout, or in Strategus's case, mass casualties and a loss of posistion for the enemy army.
Cavalry will be very effective in Strategus without a doubt, in field battles of course, aslong as it is used properly. Charging cavalry at an enemy force in a good hard-to-flank posistion, who are armed with bows, crossbows, pikes and what not would be stupid thing to do and I'm glad Strategus reflects on this. Just look at some of the English victories over the French during the 100 years war, posistioned well with covered flanks ( forests and other obstacles ), ranged superiority and the French Knights, who were highly trained, experienced and equipped, got owned, because they kept charging straight across the field at the English armies.
The kind of equipment and technology in weaponry that cRPG has suggests that the era of Heavy Cavalry trampling over whole armies is long gone and they must be used wisely if they are to be effective, but when they are used effectively, they can cause an insane amount of damage, just like in normal battle games.
But this is the reason why my Strategus character ( my main ) is a 1h/shield + some pole, with some riding, so I can use him as either Infantry or Light/Medium Cavalry.