There will be new main content to rank up?

[Betelgeuzah]

My guess is the main way to progress in group will be to simply go out and kill things in the field like in XI now from what I am reading.

He said no one item is going to be "central" way of progression anymore. That said, simply replacing leves with something even more pointless to act as the "main way" to progress would not make any sense.

I'm going to assume that dungeons and behests (and hamlet defense and other group PVE things) are going to make up the core of group leveling in the future, since they're moving away from grinding.

You'll be grinding something else instead. It's not going anywhere, but the options to do so will probably increase.

It's PR talk and means little at the end of the day.