Because I run with a DK and I try to keep D&D up, my HW and Cons is on another button instead of manual, since I need the click to place D&D. That is also an additional trigger for Fire Nova and bombs for my Shaman.

I don't think Avenger's Shield has AOE silence anymore. Rather, it doesn't work, it only interrupts the first mob it hits, not the ones it bounces to. Not sure if this is a bug or not, supposedly it's been reverted and re-reverted, but as it stands ATM, it's just one target.

According to Wowpedia, vengeance does not trigger from players. It can also be dispelled.