A duelling system would be fantastic, it's a bit of harmless fun! Yes put in an auto-decline feature for people who have no interest, issue solved easily. If you feel harassed, we have a blacklist option for a reason. We are not forcing you to PvP.

If you want another reason as to why many of us like being able to duel in the open world besides "it'll look cool", it adds the element of landscape into the mix. When you allow player skill to shine through because you can use more than just your job, but also your surroundings, awareness, and initiative, it tends to fix balancing issues. The walls in Wolves' Den are there for that exact reason. Many of us would like to see more than just walls and platforms in PvP serving this purpose, we want to be able to use the beautiful new areas of 3.0 that have been created to its full potential: becoming something that our character is actively involved with. You can argue that this is already possible with PvE, but there is a big difference as to how an AI works with the environment and how a playing character does. Monsters ignore their surroundings: they can unrealistically scale heights and move through objects like the world isn't even there. We want to feel more of a connection with Eorzea, and sending us into a Wolves' Den instance isn't going to help that. However I do understand people's complaints, and certain restrictions on where you can duel are necessary. Inside major cities should be off-limits (Unless the Coliseum in Uldah finally gets a use), we don't need people fighting in front of the Marketboard ^^;. All that being said, I'd be willing to sacrifice open world duelling for an instanced version if the majority of the community is truly against it. The Devs could even make the arenas look like certain portions of a map like they do with class quests. That would also be great, we could still look epic in the Sea of Clouds and everyone is happy.