ZNM and VNM each have their flaws, but also each have their advantages, I'm hoping it'd be some sort of a combination of the two, and hopefully of the better parts.

Such as Multiple spawns in perhaps multiple areas. Some battles that are (at least somewhat) challenging (at the time of implementation), progressing to higher tiered mobs. Good to decent drops (again, at time of implementation). Not having to travel to the furthest reaches of the game (for the most part).

I'd personally hope for some way to get an initial pop (whether it's a tradeable item or another abyssite type key item that gets upgraded doesn't matter to me). The way doesn't have to be as easy as getting the initial abyssite from an NPC, but please don't make it stupid like taking pictures. Upgrades should hopefully be as easy as upgrading to the next tier of ZNMs, sans the tier 4 drop rate on trophies (unless getting to the mobs is much easier due to lack of pictures or some similar thing). Drops that are hopefully useful, etc.

Since they mentioned battlegrounds and Grounds of Valor, I rescind my initial guess at using KC's and HKC's to pop these mobs, instead, I'm going to guess it either uses an abyssite like function, something completely new or perhaps involve Magian Trials. If it involves Magian trials, I'd envision some pop item you get from the Moogle, which you get a trial on, pop mob and kill it (perhaps a number of times for the tier 1 NM and decreasing amounts for higher tiers), trade to the Moogle and then either get a new item or simply a new Trial listed on it, and perhaps the trial itself contains information on which mob can be popped.

I dunno, just theorycrafting. With their love of Magian trials as of late I wouldn't be too awful surprised, might make it somewhat easy too, perhaps multiple people can get credit so you can build multiple pops per group for higher tiers. Though it could go the opposite way and be butchered and annoying as hell.