I have a feeling some of these locations will be turned into dungeons for 6.X patches.
Corvos as speculated by many might turn out to be the relic zone
Present Day Elpis may not exist anymore or at an unknown location ( Given it should have some Ancients ruins or intact structures and no mention of them means it might still be undiscovered to the present day )
I can't say anything else for the others. Meracydia and New world are very unlikely to be anything featured in 6.X patches as they can be their own expansion ( Meracydia expansion and New world expansion )
In fact, while Meracydia can be its own expansion, I don't think it would do justice to feature the new world in a single expansion. Then again the first was features in a single expansion despite it have a landmass big enough to host two-three expansions.