Any chance for one of the empty campaigns being converted into a free for all campaign? Minor in-campaign alliances could be formed if they still care to fight between keeps. It would be more interesting to instance a Craglorn and make it free for all. So players could have the options to open world.
The 4 classes being mirrored and all realms having access to any race already says the set up is there for this. So how bout it, flip on a switch and make everyone red to each other?
Not duels- that's feckin child's play. Good, hard core, rewarding, consequential, Mordred style, every one is fair game.
Just a few unrefined ideas with tons of potential. In all honesty, Cyrodil in it's current state is nearly as dull as the pve. Pve still wins due to the infinite quest speeches from npcs

and unending supply of "milk carton" style quests of everyone and their dog missing