Kind of an echo of other peoples thoughts, but I wouldn’t mind:
1) Going to a new location where we are the unknowns. Reboot us down from heroes and champions to relative unknowns. Even if Jaina, Thrall, and company come along and are like “these are the heroes who saved us all,” the new people they meet are like “I don’t care. Here, go pick up poop.” Make us explorers, not saviors (at least not at first, anyways).
2) Merge the factions. Horde and Alliance can play together.
3) Potentially introduce new factions in the new land area to keep some PvP style going. Horde/Alli are friendly, however we as players get to choose which faction to side with. Choosing ONLY affects PvP and story focal points, NOT the overall progression of the story. For instance, big bad gets defeated by X group; however, we can see different viewpoints of how it went down.
4) Some kind of player housing using phasing technology. For instance, everyone can purchase same plot of land, but is phased/instanced unless you invite someone to your group. Multiple random things to purchase with in game currency or earn via achievements to decorate with. Housing can be done in any faction style, such as brick and mortar like Alli towns, tree shaping like NEs, tents like Tauren, etc. Player housing can be done in new zone area or old world.
5) Let a character learn all professions.