@LetswaveaBook's mod showed us a few things about balancing, in particular across civs. One thing that I thought was great from this mod was allowing persians to train both spear and skrim cav during p1. Currently pers are basically only good in the very late game, and if you want to do a p2 archercav rush. I think it would reaffirm pers as a cavalry civ and a good/decent rushing civ. It would also bring more benefit to the stables which used to be persia's unique building.
Thoughts?