Relics will have a slight difficulty, because you still need to defeat Garuda and Ifrit Extreme. The step that requires collecting seals from Hamlets is being thrown out completely. Also, relics will be required to challenge The Crystal Tower.
The known 2.0 hierarchy: -The Great Labyrinth of Bahamut -Crystal Tower -Relic -Primal
Yoshi also stated in a live letter that there would be a tier of craftable/meldable weapons in-between each dungeon tier. I'm not sure how, or if that works out past Relic stage, though.
Joshster replied
568 weeks ago