Massive Team Capture and Hold PvP

Played this in another free MMOrpg (cant recall the name:)

Basically you have coop/single player normal world + several Character-Level based PvP Area's
(lvl 1-20, lvl 20-40, etc).
You can enter PvP through a teleport in the normal world at any time.
in PvP 2 teams spawn and respawn inside they're teams castle with several exits to avoid enemy spawn-camping.
And try to capture the other teams flag and bring it back to they're own.
Holding Both flags an PvP area would give
all players of that side a bonus in both normal world and
Pvp area (like +10% exp gain, magic find or whatever).

When you die in Pvp, you respawn and loose xp.
When you kill you gain xp.
Xp gain/loss depends on level difference between you and
your killer/victim. But only xp, you cant loose a level or level up past the max level allowed in the current pvp area.
Also there is a small chance you loose a random equipped item on death to your killer.

Pro's: Large battlefield with all types of different builds and strategies (Sneak past defences steal flag, warriors protecting mages, etc:), lots of fun :)
Teamplay for everyone , no need for a clan etc, you can battle at whatever character level or player skill.
Fun alternative for level grinding other than AI-genocide :P
Risky item farming, at high level you can find great stuff, but also risk loosing your own :)

Con's: In the game i played you CHOSE you're side at start (good or evil), witch s*cked because there usually was a very dominant side outnumbering a few poor noobs.

Solution: you start neutral every time you login. (no bonuses, no pvp portal). And add a "join pvp" button witch auto-assigns you in the team with fewer players.
And if you want to be on same side as your friends (duh:) you form a normal coop party and then hit the "join pvp" button, assigning the party as a whole to one side.