Once you get to like 50% or so close, most of the mechanics stop except for valkyr and the casters bubble thing (which is easy to stop). I used drums, pots, CD's, etc on the pull and aoe'd until drums wore off then repented Sigryn.
Just prioritize getting the runes. HoJ the melee dude when he enrages and then run away, it'll wear off by the time he gets to you. Set focus on Sigryn and repent (making a macro makes it even simpler) when she cast "blood of the father".
It can be tricky, I've had runes up while valks were coming and the melee dude was enraged. There is usually one tricky moment in the fight if you get through it you got it, in my experience.
Remember you can also basically aoe them all most of the fight and it goes faster. Just need to keep eye on Sigryn (which is easy if you set her as your focus)