Given that they said NMs will be popped by trigger items, I think it's pretty safe to assume that loot is going to be exclusive to parties/alliances.
I'm not going to shed a single tear for old Dynamis, it's always been flawed. Relic weaopns were too difficult to obtain and 90% of those who obtained them did it by either exploiting others or piggybacking on the hard work of their friends (something I'd never ask my friends to do, honestly.) AF2 was mostly useless, although with the recent announcements, it's pretty clear that you'll probably be able to augment them somehow to bring them up to par.
Dynamis can currently be done with very few people anyways. I six manned Xarc the other week. I welcome the new adjustments. It will be nice to casually do dynamis with pick up groups. There's no reason your linkshell cannot still continue to function. With the amount of people you have who still go there's no reason why you couldn't do events. I'm sure your core players will still enjoy going together. Maybe I'll come along too?