I am a bit new to the forums, themselves, so pardon this entry if it has been broached/asked before...
Comics from all brands are riddled with instances wherein a hero, for one reason or another, clashes in battle with another hero, though one (or both) may be deemed somewhat "borderline" when it comes to the hero label.
Oftentimes, however, both are legitimate heroes in their own right and, also oftentimes, the fight is simply based on mistaken identity or some other confused plotline. Other times the fight may be caused due to a character's personal agenda or priorities (say, Namor vs. a ton of characters...).
Based on this history of hero on hero violence, I wonder sometimes why heroes (or villains) don't have a simple way to duel each other in CoX like many, if not most, MMOs do.
Yes, I realize that there is an arena available for "dueling," but the simple act of getting together to fight at an arena pretty much turns the event INTO a duel in itself and completely puts the kibosh on any decent RP oriented event since the fight's location becomes so...dull.
I would personally love to have a situation wherein a hero in Kings Row is confronted by another hero while roofhopping and patrolling the streets. OOC whispers are exchanged, duel is begun, RP flourishes.
Most dueling systems have a way for players to give up, if desired, and no experience penalty for doing so or losing. The fight would be 100% voluntary and would not affect the surrounding zone or players at all (heck, a third party could take over to "help" after one player concedes).
I don't see an issue with this and would probably be more inclined to participate in such an event instead of an arena one (truthfully, how many are using them?). Who wouldn't want to be able to freely move around within a known zone instead of an enclosed room while fighting (flying high into the sky to fight Superman style or rushing for a zone exit to escape)?
Such events would be conducive to RP and helpful to those players who like to RP "grey" or "anti" heroes ("You there! Put down that gun!"). Being able to duel on the fly would likely be something that many non-RPers would also like.
Such fights would also enable individuals on different teams "square off" with invidividuals from another team, which is also a very common situation with DC and Marvel (sometimes both at once) comic stories.
As a variation on this line, other games (namely Tabula Rasa, for one) actually has a way to flag a group to fight another group, which is also fine for other types of fights.
To sum it up, while I do appreciate the existance of the arenas and while the fight club was an added variation, neither are even remotely true to any "PvP" type element within comics, themselves, and, ironically, I feel this is one area that RP (at the very least) could flourish within the PvP elements within the CoX universe.