Like most of us, bounties can be painful to farm especially if you're using a slow build and have to travel across entire maps to get to a boss. I've tested a few builds online but they were lacking in a few areas imo.
I finally came up with this variant with the Bones of Rathma Set. The great thing about this build is that you don't need to change much if you already have a Rat dps build which focuses on CDR. CDR is great for this build as well because it gives you more Blood Rush to proc Steuart's Greaves and more Bone Armor usage for Harvest of Anguish. Bone Armor procs Lost Time as well. Even so, this build isn't CDR dependent at all. You could optimize for damage and replace CDR with damage stats if you don't need a Rat dps build.
There were 3 main things I was looking for in order for the build to be efficient for farming bounties:
This build has a good balance of all 3 requirements. It's super fast, melts monsters, and not squishy.
The only skill that's optional here is Simalicrum. You can switch that out for Command Skeletons or Frailty. It doesn't make a huge difference. The build will still be fine with nothing in that slot.