This build has always been about killing before getting killed. It is very squishy unless you have the gear for it. I'm assuming this is solo play and not split bounties or group T10 (cause of the unity talk). Even with mostly ancients and pretty high gem levels, there are instances where I will die in split bounties if I'm not careful, like the fire chains affix.
Yes, Vile Ward will help with dps. More targets hit the more damage you do. I would go with that instead of gold wrap. To help with survivability, I would go the route of the GR build with esoteric gem and ancient parthan defenders. Also need more crit chance on jewelry slots and helm.
Not sure how the above poster resets WoTB without boulder toss. Yes, it fulfills the F&R spending part, but the main role of boulder toss is to reset the cooldown on WoTB so you can have it at 100% uptime.
If you are still dying with GR build, you just need better gear. Nerve of Steel passive also helps a lot. Get it with a hellfire ammy or switch out pound of flesh for it. Will slow down your runs, but dying slows down your runs more.