About your siege idea, the bloodthirsty trait for jewelry does work with siege. I personally like using my tank and coldfire works awesome.

My gf actually was wearing war maiden and vicious death, war maiden jewelry. But we were just seiging and she noticed the damage was higher after that change. Standard ballista hit 2000 dmg gold bloodthirsty trait makes it 2600 area. Swarm mother procs from blocking enemies and pulls them to you. I think this one monster set can still proc if you fire siege and they block it but it does no damage. I remember reading something about it. Search the forums if any monster sets still proc from siege should get it. I would say no to major and minor berserk buffing siege. From my understanding they already have siege at the damage the devs want and don't want us to make it even more OP. I was surprised bloodthirsty worked but it is the last 25%. Check the forums more than likely someone's already tested it.