Very nice guide koroshi, I've been using undead runes for a while with good success. But the new runes of perplexity have me wondering how all that added confusion would work out. I mean with the shield you can almost guarantee a couple of interrupts, not to mention all the other CC we have available for interrupts and good sources of confusion. I believe the #4 bonus is 3 stacks and #6 bonus is 5 stacks.
Also the new sigil of malice, would get you back your 76% condition duration without runes
I tested the rune out, it is completely broken. 25 stacks of confusion are easily achievable.. it is just crazy. I might just record a video about it.
It is possible to use rampager, however I am against using it. You need to be able to survive an enemy burst, luckily engi's base health is high enough to completely ignore vitality. Toughness in combination with our healing makes us a very strong class in defense and when you start combining that with blocks, perma vigor... this is what makes the engi strong from my viewpoint.