I am confident that the core of a PvP system are already defined, but I still want to express this thought.

Have PVP Zones - This could be the disputed lands between factions. Enter zone and you are now flagged PvP. Leave zone, it is removed.
It is still just faction vs faction PVP.
(nothing really new there, and I think that is how it is handled here)

Gank PvP - There is probably a better name for it but hear me out.
Allow unsolicited/unwelcomed PvP, but with a penalty.
Attack any player, in your faction, any time. You get 3 free no penalty attacks. (win or loose)
After each attack, there is a 5 minute timer of Appeal where the player you attacked can say, "It was a fair fight!" If they flag it as "fair" then there is no penalty. If they do not... you get your first Warning.
In addition there needs to be an onscreen warning "Are you sure you want to attack Bluewalrus Queen?"

Repeat Rinse. This allows for a dueling system (nothing really new there)

Once they hit 3 Warnings, they are now full PvP. They are Wanted. (that should be familiar to ya)
But... whats Full PvP mean?

Full PvP - You are now flagged as a Wanted Person. It matters now where you go.
Any player can attack you!
You can only attack other Wanted Persons, unless of course you are attacked by other players.

(Gank PvP or Wanted only possible in open areas. ie: towns, roads. Not available in quest/dungeons/instances)
(The PvP Zone rules would still apply, so when in a PvP zone you can only fight the other faction)
(Gank PvP or Wanted would give a ranking but no XP.)

A player who attacks a Wanted player does not get a negative flag for engaging in PvP. That is strictly for unsolicited Gank PvP.

So why would someone want to PvP? or be Wanted? Other then challenge, the Rewards are limited.

-Once you become Wanted you are now in a Rank System
-Defeating a Wanted player gives a Reward
-The more kills, the higher your rank, the higher the reward.
-NOTE: Once Wanted you can only fight other Wanted... unless attacked by other players (assuming people would group up to clear them out)

Rewards - As a Wanted person climbs the Most Wanted Ranking, the rewards increase.
Possible ideas could be:
- money
- trophy items
- Title
- Forgiveness (collect a reward for defeating a Wanted Player and have your Wanted position reduced and or forgiven)
- other fluff items

So what happens if I am Wanted and get killed in a PvP fight?
- Your ranking drops on the Wanted list
- You are safe for X amount of time (to prevent exploit)
- Small stat penalty that wears off over time
- Loose enough times and you will fall off the Wanted list and loose your Free for All PvP Flag... you are no longer Wanted

So what happens if I win in a Wanted fight?
- Your ranking goes up on the Wanted list
- You can turn in your win in for one of the Wanted Rewards, or build them up for a better Reward

Other options:
- Buy your freedom. The world is corrupt, pay your way out of the Wanted list. Can be used to reduce your level of Wanted or to take you completely off the list and loose the PvP flag.
- Crafting. Disguises! How about player made disguises that would allow a player to enter a town, road, public instance for 10 minutes (time can vary). This would allow them to buy and sell and conduct business. But wait... how Wanted are you? The effectiveness of the disguise would be determined by how well known, or Wanted you are. IF you are number 1, no disguise will ever help you! No. 1 comes at a cost.
This would allow for levels of disguises and create an interesting economy.


I know that is a lot to read... thoughts?

It's an interesting idea, but it's not going to be implemented into the game. This wouldn't appeal to the general base, and thus it wouldn't be seen as a priority feature.