Nexus and Novus steps both need to be nerfed. I'd argue that out of the two however, Novus is the worse grind. The reason for this is simply the amount of Materia you need for the Novus. The Alexandrite themselves really aren't that bad, in fact if it was JUST the Alexandrite I'd rate Novus as one of the more enjoyable steps.
However, with Determination-4 Materia being 500+K a pop, and Crit-4 costing a similar amount, you either need to grind out an absurd amount of Gil, (absurd for most players,) or you need to do a rather large Spiritbind grind.
Thing is, Novus at least has a chance at being done quick enough depending on luck (SB wise) or gil.
Nexus has absolutely no chance at being a quick grind. It's long no matter what.
Ideally both should get a nerf but Novus is more bearable imo than nexus.
edit: I would love all the steps to be nerfed even more by 3.0. Just to make it easier to get my other classes relics past the Zenith stage.