I soloed the Hollows arcs a couple of hours ago and was doing the Frost mission. Last room, there stands Frost surrounded by his buddies and a Quantum. Lesson learned about Starless Step's usefulness!
It is a quirky power, though. Teleporting sometimes aggros the group and other times they'll happily stand still, completely oblivious to the fact that their pal is 100 yards away getting beat down. Lots of ins-and-outs to learn but that's part of the fun.
Thanks! Sounds like I'm on the right track:
1-5: Not many options at these levels, I relied on Ebon Eye and the p2w powers to mow things down.
6-11: Still only two attacks for human form so I'm only occasionally shifting into it to drop Gravimetric Snare on a tough enemy but otherwise blasting away in Nova form.
12: Sunless Mire looks like the next big bump in power.