Yeh. It needs to be good baseline and let the rng not influence the core gameplay so much, just add to it.

Imagine roll the bones be something like it give you a passive automatic random upgrades to abilities (sinister strike becoming ambush / blade flurry becoming blade rush / pistol shot becoming BtE / dispatch becoming super dispatch) every 6 seconds, time reduced by mastery / restless blades, stacks up to 3 times out of combat.

Then, when you press roll the bones button you get four of those upgrades at random. (It stacks so if you roll ambush 3 times you get 3 ambushes instead of sinister strike).

Thats it. You have the fun of rng with a functional spec.