I really recommend going BD/Rift/Assassin once you hit 30+ or sooner.
http://rift.zam.com/en/stc.html?t=0MiNM.V0xM.VMcfu0kskcz.0VWith rift scavenger you have 0 downtime, and you can take on multiple mobs at once.
Keep False Blade and Dauntless Strike up at all times, kill a target, loot, flash of steel to next target, kill, loot, flash of steel to next target.
I have 0 downtime, and I kill things extremely fast.
You can use this soul set up earlier then 33, around 25+ as shown in the soulset up I linked above if you get 3/3 Rift Scav before going into Blade Dancer.
3/3 Rift Scav is pretty much the bread and butter of this soul set up, gives you 0 downtime for nonstop questing.