If there's a time when the Imperials are particularly interesting to observe, it's during this Interregnum, and even more so now that the empire no longer exists.

All that remains is Nibenese.
We've had the Cyrodiil PvP zone, the DLCs with the Imperial City and the Gold Coast, as well as the expansions of Blackwood and the West Weald.
They all have this in common: the main enemy is a Daedric invader. At least not for the Gold Coast, which offers one of the best settings and a good series of quests.
(I feel that, for Colovia, they could have done something similar to Orsinium: Colovians vs. Woeful Colovians. But the interesting concept of Woeful Colovians seems to have been forgotten. It would have had a less epic, but much more surprising and welcome, storyline for purely Colovian content).

I doubt the main hub will be Bravil. We should, on the contrary, look towards Mir Corrup and Caer Suvio. Hopefully, one of them won't be forgotten like Sarchal in Colovia.
It would be a golden opportunity to show us a Nibenese hub with an authentic Nibenese architectural style ! Especially since Nibenay suffered from showing us cities influenced by other cultures in TES IV. As for Bravil... it's a slum.

With the West Weald, I regret that this vast territory depends entirely on the sole authority of Count Calantius of Skingrad. Even Sutch, which I was ready to bet would be a county and whose count would be a certain Charonius.

I therefore dare to hope that this vast Nibenese territory will, once again, depend on the authority of a single count. Moreover, we should encounter Count Opius Voteporix (unless he has been overthrown or replaced).

Will we see another Tharn? We haven't heard from Abnur Tharn, Chancellor of the Elder Council and also Overlord of Nibenay.

What can we expect from the Nibenay storyline?

Nibenay is the most imperial of realms, while the Colovians have always maintained a degree of independence. It's a land of intrigue and betrayal, a nobility capable of buying the services of warriors or mages.
The warring alliances of the War of the Three Banners would make perfect enemies. But since our player character is inevitably tied to them, we can rule that out.
A cult of Marukhatis, worshippers of the Alessian Order? That would be interesting, but perhaps not epic enough for ZOS.
The risks of another Daedric invasion are high.

Without necessarily overthrowing Opius Voteporix, as with Euraxia Tharn or Svargrim, I would prefer a treatment similar to Caddach's, rather than Calantius's. While the context and implications of the Nibenais are unclear, aside from this business with the Euraxian mercenaries—though the subject has already been raised in a Blackwood village—I hope that this time Count Voteporix will fully assume his responsibilities without ever apologizing in any way. After all, his only concern is the well-being of his people, of Nibenay. Calantius disappointed me in this regard, dependent on a lost bear cub that has weakened him, barely addressing the issue of Arenthia, and dismissing any legitimate conflict with the Dominion with a simple decree of independence.