I think a kinda thematic resource flow for DRK could be like MP(HP) spenders, Dark Arts spenders, and Blood Gauge spenders. MP is a stand in for HP, any action that restores HP should also restore MP at the same time, and rate. When you use an attack that costs MP, you gain Dark Arts which you can hold up to 3 Dark Arts stacks. Dark Arts can be spent on tanky actions, but can also deal some damage. The Blackest Night, Salted Earth, and some kind of burner action now cost Dark Arts. TBN now procs Abyssal Drain when broken, Salted Earth now provides personal mitigation when you are in its area of effect -- and it's made slightly bigger, and the burner action now just deals damage, and restores MP/HP. Keep Blood Gauge simple, using weapon skills, builds gauge to spend on more weapon skills.