Hmm, I'm not sold on piercing arrows personally, so that's what I would drop. I mean, I can see how it can in some situations help group DPS, but it just seems too situational to me and a 10% dps increase not only works in all situations, but also works in the most important situations: when you need a specific target to go down.
I understand, that 5 more points in Skirmishing taunts me every time I look at this build. But honestly, what would you drop for it? If you don't have a reliable condition removal, you're severely hindering yourself; if your arrows don't pierce targets, your limiting your group dps abilities (this one is still up for debate according to your play style, teams you face, etc.); if you drop quick draw, you're hindering your evasive abilities (as well as the obvious other utilities from poison, daze, cripple).
As far as the thief runes go, precision isn't a trait that you need. The extra bleed from "Sharpened Edges" on crit is extremely low, and isn't worth investing into precision for alone. Thief runes also do not effect your condition damage, as these runes are made for power builds, which this is not. I chose afflicted because almost all of our damage comes from bleeding and poison, and the 15% increase in duration is an obvious choice.
Thief runes do bring some condition damage (+57 total), but I can see your point when condition is the key. Is the death nova from the 6th rune really that good? I haven't tested it, but it would be tempting for me to go 5/6 afflicted and bring a 6th with a stat I liked for the 1st tier such as Grenth.
p.s. I know I'm criticizing a good bit of this, but I just wanted to say that this is still one of the best builds I've seen on these forums so far.
Edited by Dahk, 09 September 2012 - 05:25 PM.