Does a character have to meet both the alignment restrictions and the class restrictions in order to use the item?
I have an Ilsarian NG Fighter who is a pure archer and it is not able to use this item.
Is there a reason to restrict this item to only AA and Ranger?
The Bow icon is mainly due in my perspective to the fact that rangers in any type of games have always received a lower armor class level than warriors. Which means they tend to rely more on their nimbleness to evade the attacks, and thus are better suited for ranged attack as those are based on dexterity.
Rangers are a lot of things. That is one interpretation, and they may use bows. There are special ops rangers, scout rangers, junior druid rangers, park rangers, and everybody has a purist view of what a ranger is supposed to be - typically the narrow view is that of an elf with unsurpassed mastery of the bow, which is not really the case.
A dex based fighter can do decent damage now with ranged weapons because they can use GMW on their bow and the stack of ammo currently equipped can be hit with darkfire.
A mahogany shaft arrow puts out an additional 1-2d6 physical plus whatever type of tail you put on it as type damage. Far better than the 'fire arrow' made by the ilsare bow, and also better than the electric arrow made by the shadons trap bow.
The feathers will not give you anything when you are not facing what the arrow head is for, if an enchantment is set on it. I discovered that yesterday.