Why are cavalry units so slow and weak?

[Vincent Butler]

if a battle goes long its advisable to keep them in reserve, or pull them back to rest for a while because a charge of a fresh unit and exhausted, is a big difference.

In melee, cav vs heavy infantry will get owned, unless it is something like the Baktrian Late Bodyguard Cataphracts, who simply have the defense to keep fighting. Even so, better hoplite-style units or heavy spearmen still inflict a beating on them. The strength of cav comes from their charge bonus.

light cavalry and light lancers should be used for flanking and chasing down routers only. generally you dont want any cav engaging in prolonged melee, except if its cav vs cav and you cant really outrun the enemy anyway.

i personally really like how cavalry works in EB. FM cav can win you games with charge and retreat and repeat. but if you dont use them well, then their impact is limited.

That was a surprise, coming from RTW. In that game, cav owned just about anything other than spearmen, elite cav even beat elite infantry, usually. Different in EB Even skirmishers in EB can put up a good fight against cav, or even beat units such as Equites Romani or Hippeis, and more archers in EB have spears instead of swords as a backup weapon, so cav have a more limited role in EB.