I think one way that they could nerf the umbrite step a little is allowing us to buy the umbrite with poetics as well. Think about it, you need to do the CT quest 5 times to get the 5 aether oils for the hyperconductive step and each CT dungeon is worth 100 poetics each, once you complete the CT quest for the Aether Oil, you have enough tomes for an umbrite.

Then again, just nerfing the price would work. I also expect they will introduce a quest similar to the CT trio quest for aether oils but using the Mhach storyline raids and the reward will be umbrite. (Since 3.5 introduces the final part of that raid trilogy.)