This is an idea I'm sure many of have had in the past. This would replace the Warfront system to be in the actual world but, also be reflective of PvE content out there as well. This is the Classic example of Duskwood being broken into subsections for each faction(Alliance, Horde, Defias, Undead, etc) to conquer. This would present different variety of quests based upon the circumstance of subsection and also provide invasion points from other zones to impact it.
The content would be playable at all levels and in several instances create "World Events" where the power in a particular region is tipping beyond the breaking point would could lead to subsequent invasions in nearby zones. Ultimately this content would be reset every few weeks to a month to provide a restart to whatever chaos is occurring. Players can actively choose to play in any zone with the only limitations being friendly factions. Such as your parent faction and other such factions as the Cenarion Circle, Argent, Goblins, etc.
In case of Duskwood we could have a...
1. Hakkari troll invasion
2. Horde invasion
3. Demon invasion
4. Naga invasion
5. Kurzen invasion
6. Blackrock Orc/Dark Iron dwarves/Dragon invasion
7. Cataclysm elemental invasion/Cult of Twilight
Within the zone we could have...
1. Mindless undead rampaging the countryside and possibly killing everyone in Darkshire
2. Ogres conquering their neighbors
3. Defias rebellion takes over Duskwood
4. Nightmare bleeds into Duskwood
5. The Necromancer (Morbent Fel or Abercombie) plans to use the dead to rule over Duskwood
6. The Worgen pandemic reaches to incredible levels as Darkshire is turned completely into Worgen
I apologize for the MS Paint picture.