I did a STF as a 15/24 awhile ago (last patch 2.33) and it was awesome. It doesn't do as much damage as 18/21 but is much faster and more accurate. It's more of a "spam" role than a damage role, but it's effective against low armor and good at supporting your melee friends.
On another note, if you DO intend to stick with archery, there's almost no reason at this point (besides being a horse archer) to use the Horn bow over a Rus or Long. Going either, I'd suggest 21-18 or 24-18. While the first gives you more of an ability to hit hard (though not fast) in both Melee and Range, the second one, once again, makes you a Pure archer.
Longbow is useless without 140 wpf. With 150 things get better but I think that with 160 it should be ok.
Also archery isn't under powered. I do the same as archer as I do with other builds. Some people are epic at melee so they feel that achery is a bit inadequate.
If you can't kill shit then you're crappy archer. Changing your build won't help you much, many people are lucky that this is battle so they can get some free kills but amount of total nubs on server at any time is about 65%.
Archery doesn't suck, it's balanced. Players do suck.
You want old OP archery so you can rank up some kills even if you're total moron. Sorry but that's out of question.