Two very cool mechanics, I can say, to start with -- this will get edited more today...
Trial of the Magians
Right of the bat: If you aren't trying to level up your Mythic, you start with a base weapon.
But you are provided that base weapon (and it is Ex) out of a weapon chest, and you trade it to the Moogle and then go from there.
Quests either involve killing a few NMs or a LOT of normal monsters, often under conditions like weather.
Proto-Abyssea (Not official name -- one I made up)
This is the new NM stuff. You buy a key item for 1000 gil. Then, anytime you rest/ /heal in the field, it will tell you if there is what is called a Voidwalker in the area. If so, it will tell you how far and in what approximate direction.
Then you go off and /heal every so often to see if you can find it.
Be careful -- they appear, at the very very least, to be T-VT to a 75. I ran into a slime (Globster -- about 4-5K HP approximately) in North Gustaberg and a Thunder Elemental (Thunor -- Does IVs and aga IIIs -- about 4K HP and killed me). No real tricks that I saw, but they are hypergame material.
New Campaign Items
You can BUY with Allied Notes the Campaign Weaponskill item. It's a level 73 -- Bastok's is a sword with Glory Slash.
The catch: You have to have THE HIGHEST MEDAL (unattainable for the next five days -- the first of the people who get the medal below it got it when the restart happened 90 minutes ago) of the nation for Campaign to get it.
There's another item you can get for each nation's highest medal as well.
The XP ring previously referenced is NOT buyable.
More to come. An early doubleheader Besieged (didn't they say no Besieged in the first three or so hours after a maintenance??) to probably get 68 RDM.