I don't like it as an "arena" because Guild Wars simply isn't balanced for 1v1. For example, a mesmer will be the best, and in some cases, a monk will be unkillable. So as a form of PvP itself, then I disagree, but if you want it to settle arguments, then at best, it will probably have to be implemented very casually, not as an "official arena," probably similar to (please don't flame me for this

) the duels in WoW that can occur just about any time. And again, PvP is
not balanced for 1v1, so it's very unlikely that the duels will be implemented either. So basically, sorry, it's not going to happen.
Also, if you're trying to duel a griefer or a n00b to settle a dispute, even if you win, they'll still continue with their retardation. This occurs in just about every other MMOG:
"OMG you play so lame!"
"WTFZOMG that skill is too cheap! no using it!!"
"nuh uh!! even though I lost and am obviously the retarded n00b, I'm still going to whine like a little bitch!!11!!one11one!one"