I don't mean Cyrodiil as in the PvP aspect of it (though large-scale PvP has been long overdue some new content), I mean the land itself and the Imperials that dwell in it.
In terms of places we can actually explore (Not counting PvP due to the constant threat of enemy players) the only location with Imperial architecture and culture we've been to is the Gold Coast. Furthermore, aside from the main questline itself, we've had barely any Imperial-related quest content.
There's a large group of Imperials in Cyrodiil that are actively fighting against all three of the Alliances, yet we've had no content revolving around that faction of Imperials.
I propose that after the next chapter comes and goes (pretty much NEEDS to be something in Hammerfell otherwise it wouldn't be fair to the Daggerfall Covenant), that the next one open up a large portion of Cyrodiil that we have yet to explore, and have a storyline that heavily focuses on the Imperials. If I have to propose what the story might be for this expansion, why not something foreshadowing the Knights of the Nine expansion from Oblivion? A faction of Aylied warriors under the influence of Meridia could be involved.
Guildmaster of Spectral Liberty - Xbox One - European Megaserver