Lanjane
I'll have what she's having.
Who may be mightier than deadly parthian horse archers? The answer is simple: foot archers!
A lot of them! You can maintain three foot archer units instead of one horse archer unit, because cavalry are extremely expensive in this mod. Yes, HAs have powerful charge, better morale and are able to perform complicated maneuvers on the field, but foot archers always offer superior density of fire, as they have twice more men in one squad, and almost unlimited ammunition.
In my Bactrian campaign, I've just beaten three Free People's fullstacks which have golden veteran elephants, HAs and indian archers, with only one bactrian stack (the losses were very-very insignificant):
As you can see, almost 1/2 of my army сonsisted of foot archers. Phalanx pikemen to protect them from frontal attack, and a few cavalry units to draw enemies attention and to pursue when they run. That combination is nearly unbeatable both defending&attacking!
Archers bring death on numberless arrowheads!

Thank you AqD that there still exists anti-tactics vs horse archers and other powerful foes in your mod
In my Bactrian campaign, I've just beaten three Free People's fullstacks which have golden veteran elephants, HAs and indian archers, with only one bactrian stack (the losses were very-very insignificant):
As you can see, almost 1/2 of my army сonsisted of foot archers. Phalanx pikemen to protect them from frontal attack, and a few cavalry units to draw enemies attention and to pursue when they run. That combination is nearly unbeatable both defending&attacking!
Archers bring death on numberless arrowheads!

Thank you AqD that there still exists anti-tactics vs horse archers and other powerful foes in your mod