I'll review stuff we know.

Alternating hardcore raids and alliance raids series is continuing.
However at fan fest they teased maybe adding a 3rd difficulty even harder than savage.

Dungeons no news of changes, but Deep Dungeon will continue.
Exploratory missions will continue, we see new design for those in patch soon.

Upgradable weapons will continue, but will not recycle old content like zodiac and anima did.
Yoshida teased possibility of upgradable armor system to be added later if successful.