Gotta go big warp bubble for the offense, I find it too necessary for being able to pop the armor/barrier crowds. For the heavies with the asari dodge she is agile enough to get in and out dropping a warp bubble on reaved targets before getting clipped. I only go 3 or 4 in pull for the annoying mooks or those who've lost their shields. idk your manifest but do you have access to a weapon that staggers groups falcon, venom, scorpion? You might consider bringing one of those to stagger groups of enemies you've reaved giving to dash and bubble them.
Another option would be going for area pull it won't lift shielded enemies, but it usually triggers either a dodge or interrupts attacks enabling you to close the distance and bubble them. After you bubble a group dodge out immediately whichever way you choose and immediately hit it again w/ reave to pop the remnants who think they've survived, they haven't they just don't know it yet. 
A more conservative move would be to bubble up choke points until you get more comfortable dodging in/out of crowds. Never hesitate to reapply the bubble or move the bubble to wherever you need it most. It's not static and stationary, it's a mobile killing field. I never stop moving with her, but for a moment to get shields back. Definitely one of my favorites. She is the Reaper, Reave is the scythe, the Bubble is the gate to hell, send them on their way OP.