Relic: Chimera is nerfed, Amdapor Keep is nerfed (to oblivion) and Hydra and the Primals are given the Echo. Easier to acquire Relic now, whereas it was an effort back in 2.0
Zenith: Easiest step. 900 Myth and you're done (now will most likely need... 450 Soldiery in 2.4?)
Atma: Spend minutes, hours, days, months hoping to get a single Atma that will go towards you getting the Atma weapon. Nothing has changed.
Animus: Easier to get Myth for books now, I hear FATE's now have a quicker pop rate than before, meaning it is much easier to get an Animus now.
Novus: Daily roulette to get map for Alexandrite. Buy map with 800 Myth OR buy the Alexandrite with Allied Seals. Can either make your own materia or buy it. Can also decide if you want two stats that require Tier IV materias or three/four additional stats that only require Tier III's.
Nexus: Do Cape Westwind (and other stuff) for a few hours a day.

Atma (and Nexus, but that is still fairly recent) is currently the only step that has not been nerfed in any way.