Let me just point something thing out;

Mythology Tomestones are getting crafting items similar to Philosophy.
Gerolts stuff is presumably crafted.
We're getting a new Tomestone category, which so far has no purpose if you assume Mythology items are used to make Gerolts gear.

My assumption;

Gerolts gear is iLv90 and can be melded, making it slight better than current iLv90, just like the iLv70 gear was slightly better than Dorklight.
Allagan Tomestones of Newness can be traded for a yet unknown gear set which will be equal to Coil Turn 6~9 gear. That gear may or may not be AF2.

They've already confirmed we're getting Zodiac weapons this update, but they've yet to show us any. Would be pretty logical to get AF2 alongside it.