Honestly, I welcome additional discussion on the mechanics of Rune Weapon - it's one of the most misunderstood abilities in the game at the moment. I'd like to do some additional testing myself to verify some of its behavior. We know it scales with Haste, AP and Strength. The general consensus is that it does NOT scale with armor pen, and I've seen arguments for both sides on whether or not it scales with crit rating. Furthermore - some people insist it doesn't scale with Hysteria or Blood Presence, and some insist it does. I haven't seen convincing proof either way, however.
And finally - it seems to scale to 50% of your autoattack damage (minus armor penetration most likely), however the rest of your abilities aren't affected by talents or glyphs, which ironically makes death coil one of the hardest hitting abilities to use while Rune Weapon is active because it is already the closest to baseline (as opposed to several talents and glyphs increasing heartstrike and death strike).