I was pretty disappointed and incredulous that the Imperial Isle is currently completely inaccessible, but at the same time, I'm sure that once it is released, it'll add to PvP what it's currently missing.
Currently, being Emperor just means controlling a few keeps in Cyrodiil, with the actual cities in Cyrodiil completely independent from you. My theory is that once an alliance controls the prerequisite keeps, they will be given the opportunity to take the city and defeat Empress Clivia (surely she would appear when the Imperial City is released - it's unusual for a character who's mentioned as often as she is not to make an appearance). Afterwards, it will serve as a sort of second camp for the alliance - with shops, perhaps a wayshrine, and with quests etc. that only the dominant alliance could access. Maybe it could also open the way for the leading alliance to seize control of the actual cities, too - it's struck me as odd that the four accessible cities in Cyrodiil continue to be independent city states even when all the surrounding keeps belong to an alliance, and the alliance may even have guards patrolling directly outside the city gates. Surely it wouldn't hurt to make alliance-affiliated city guards that aren't hostile to players from other alliances?
It would all make being Emperor/Empress or a member of the leading alliance even more desirable.
Edited by Lysistrata on 14 April 2014 23:29