I just started doing AVs too, and one thing I noticed which i found just insane was ziz..

me on my own (crappy gear) can be steamrolled by a small group (3-4) if they have a rogue with them (providing they have S2 gear or higher).. they are soo freaking annoying :S

Me+ healer = 5-7 dead depending on their gear lvl and skill
Me + 2 frost mages = invincibility against all except lots of rogues

from now on i always ask one of my mage friends to tag along and CC everything that gets near Pet novas on groups of enemies = easy pickings