I will now make the case that the Enchantment bonus isn't quite OP, well at least in the way I imagine the process working. A female isn't just instantly captivated once exposed to the pheromones. No, she is just more inclined to respond favorably and take an interest in the Banar'ri in question. The positive influence grows over time. It requires several encounters over a span of time before she is "enthralled." Even if a company of Banar'ri were to be engaged in combat with an army of Amazons, unless they already had several relatively recent encounters with them these women would still attempt to kill them. They would just feel somewhat bad about it.
So in the end enchantment would only provided a morale debuff against a female army, and a diplomacy buff when dealing with women.
What says the Judge and Jury?