I'm against giving the Flaming Arrows option to Androphags, personally. As they have so much a bonus with their poison, at least for they "specialization" they should give up some versatility, so there is a use for the other kind of archers, less powerful but more versatile.
Flame arrows really wouldn't be (much) of an upgrade if any.
Their poison arrows damage even if they don't 'hit.' making them veeeery effective against heavily armored targets. Flame arrows wouldn't.