With buffing light infantry, some consideration needs be given to tribal retinues. As they are even small tribal realms can be very OP just by numbers. Lowering the retinue cap or something there might not be bad.
I like the idea of replacing the tribal army decision with retinues, but the thing wasn't balanced properly
Will you ever give combat tactics another look to iron out some of the quirks? Especially the weird interactions with how special units like horse archers, camels or elephants are counted towards the limits of light cavalry and such for tactics selection. This causes those units to actually be penalized with the most likely tactics.