I'd personally go Accuracy (if needed) > Crit > Spellspeed. The later only works for the amount of Ruin IIIs you can fit into one Dreadwyrm Trance, so I dunno if there's gonna be a soft cap for it or not. People need to do some maths on that I guess.

Then again, I'm a philistine ¯\_(ツ)_/¯