I would not mind as long as these limitation are in place.
1. Option to automatically refuse duel invites
2. Must happen outside of cities.
3. Duel invites cannot be issued with in fates or with in 40 yrds of hunts.
4. Cannot be issued to those who are in combat,crafting or gathering.
5. Attacks of dueling players have no effects on any npc's in the present area. Npc's will not aggro onto dueling players..
6. Dueling players cannot be targeted by other players. Players who are close to the duel will get a party like window showing the dueling players HP, buffs etc.