I think the black arrow is a little bit boring...
Personally I like the original Black Arrow for gameplaying, but I think is illogical in role-playing. I think that the great mistake of I.C.E. is that they don't have standard guidelines for cards and keywords.
I try to make a version more "realistic" and at the same time playable and balanced. I like the idea of skills that represent abilities so I think that to use a particular arrow you must able to use bows effectly (warrior) and able to retrieve it (ranger). I don't understand why only a man could be able to retrieve an arrow. Bard can kill Smaug cause he's a skilled archer (and thanks to the old thrush help) not because he is a man. And I don't like cards keyed to a particular character (if not strictly necessary). An arrow is an arrow and can be used by every bowman, more efficiently by someone particularly skilled (Bard as saw in the Hobbit and the famous elven archers).
The Black Arrow you've quoted is far too powerful for a minor item. A couple of elves or an elf and Bard with two Black Arrows could give a -4/-4 to a single creature attack or a -2/-2 to two different attacks each m/h phase, better than most Major and Greater Items...
you cannot give -4/-4 cause "Only one Black Arrow effect can be applied on a given attack. ".
but maybe it's again too powerful... in the origin I plan it "unique" (I always seen THE black arrow), but can be boring for gameplay if played by opponent (especially 'cause it can be used as starting item) so I could add "cannot be duplicated on a given company" instead.
Have you checked out the Bard the Bowman in the current VC set? He's pretty nifty now, at least when used up in Dragon country.
Regards your suggestions, yes Bard is good, but he's not really much different from other run of the mill 6 mind characters. Having too many big prowess, big mind characters just limits company composition. Sometimes having lower mind and more targeted bonuses can lead to more interesting combinations and strategies.
I agree about the important of low-minded characters, but I think that Bard as guardsman of Esgaroth, Dragonslayer and King Of Dale is an important character and that the original version doesn't respect the personality that Tolkien give to him. For example, in his mithology Bard is more important than Brand (his Grandson) and the cards don't reflect this.
Again I try to create a more realistic character based on "The Hobbit".
As I said I agree your considerations but there are lot of minor characters more suitable for a low-minded part (also consider that there are few men with a decent prowess/body)
An other great injustice is Halbarad: the second in command of the Dúnedain behind Aragorn and the leader of the Grey Company a 0/5!?!
For gameplay is a great card, but it's another nonsense to me (and to many others!)
Salo
P.S.: it's interesting to share point of views like these... I plan a scenario and are very useful

P.P.S.: I change "Only one Black Arrow effect can be applied on a given attack." in "cannot be duplicated in a given company"