- civil centres can no longer train cavalry
- brit crannog can no longer train cavalry either
- brit kennel is available in village phase (cf. pers Stables)
- maur elephant stables is available in village phase (cf. pers Stables)
- worker elephants can no longer be trained at maur civil centre
- military colonies (ptol, sele) can still train town phase mercenary cavalry
- civs can still train cavalry in the village phase, at the barracks or stable
This is something occassionally mentioned on the forums and implemented in several mods, so apparently there is some demand for it.
Removing cavalry from civil centres has the advantage of somewhat delaying early cavalry rushes (because players have to construct a barracks first); it's also easier and more efficient than other proposals (e.g. introduce a corral technology requirement). Furthermore, it's more historically correct, because horses were kept on farms and meadows outside settlements and not in city centres.