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.