It would not surprise me if we need the Padjali weapon achievement for the class/job we want to go in as to enter flor 51.

It would not surprise me if 51-100 (the "main" levels) have a second 1-30 for their Aetherpool Arms/Armor. They could simply go with the current Aetherpool gear and extend it to 60 60 though. Either way, I would be rather surprised if the max was not an entry requirement at some point soon after floor 100. Might be 101, might be 121, but somewhere in there.