I would really like to see a new PVP zone. It would be great if they made one of the upcoming updates a new zone that had open world free for all PVP. The only people you cannot target or can heal are people in your group.
Have this zone be a regular zone that has a quest line in it, towns, and world bosses. PVP in towns would cause a bounty and make guards attack you.
Have outposts that a group can take control of and obtain some sort of reward for holding it. Another group can seige the outpost and take control of it. However, the outpost goes back to neutral as soon as the group breaks up so no one can hold it indefinitely.
It would still be the open world feel like cyrodiil but have an actual group play style vs an alliance play style. You could even add in some sort of currency like telvar stones in this zone.
I think this is the PVP gap that the PVP crowd is looking for. It's just you and your group vs the zone. No 50 person zergs running you down.