I enjoy Path of Fire. The critters are spaced out well enough, and not too easy, not too hard. I can solo pretty much the whole area.
I hated Thorns. Too crowded and most critters felt like mini-bosses. I got my glider and got out of Thorns pretty quickly. Only one avatar could hang in at all there, my necro/minion master. None of the others could survive at all. Not sure if they nerfed the area before or after, but I did not care enough to find out. I have not gone back since.