Up to Alpha 21, elephant archers inherited the archer cavalry template.
Hence the units had ridiculous walking animations due to their speed and many other properties which fit to cavalry but not to elephants.
These were removed:
rP18286 reduced the walk speed inherited from cavalry drastically for consitency with war elephants.
rP18363 removed the capturing ability for consistency with war elephants.
rP18453 removed the gathering ability.
rP19333 gave the elephant archer a large passability class, which means it wasn't possible anymore to mass hundred of them in one place.
However this reduced their combat use drastically and we never see it anymore in games.
It was planned to buff them last release but it fell under the table.
With these new properties, it should receive a use case that is different from regular archer cavalry and thus add to the set of valid choices,
requiring the player to decide wisely which units to train.
This is how 2x attac kspeed would look like. (There are 2 soldiers sitting on the animal, but only one of them has the attacker animation). So instead increasing attack damage and attack speed both by 50%.
