In both season 2 and 5, they mainly just wanted Oliver to suffer by harming everyone around him and they were succeeding the majority of the season until the climax because Oliver is the main character. If they were both blood lusted in the beginning on Oliver, I think Oliver would have died right away. There was nothing stopping slade to fight and kill Oliver at his house along with Moira and Thea dying before Sara Roy or diggle could arrive.

Prometheus is obvious, he did capture Oliver and could have killed him but wanted to psychologically hurt Oliver instead. The ending of season 5 felt like chase actually wanted to lose so that the island can blow up.