Rather than a queue for a single 1v1 duel against another player, I'd rather this feature be implemented as a Battleground-like "tournament" PvP mode, in which multiple players queue up, but are selected at random to 1v1 duel with other players in the lobby until the champion in the lobby is decided, where players earn rewards based on their performance, and from the daily queue.

The reason Tales of Tribute 1v1 duel queuing works as well as it does is because the two players don't need to leave the instance they're currently in to play the game against one another. Combat dueling would require both players to be in the same instance, but this can cause problems with the loading times on lower end hardware. Remember how sometimes when queuing for Battlegrounds, players will gain control of their character after the game has started? There's no doubt that a 1v1 duel queue between just two people would cause frustrations if players spent so much time in a loading screen, just to discover that they've already been killed before getting the chance to move their character.

A duel queue must be longer than a single 1v1 fight to lower the odds of this happening. There's also no reason to keep anyone waiting in a lobby that will never fill if the other player decides to quit. A combat duel queue should be either best out of 5 if between just two people, or something like a championship bracket between 8 or so players (meaning 4 + 2 + 1 = 7 fights in total) so that the queue is a more substantial use of the players' time.

I'd want a Dual Queue, being able to queue for multiple things. Usually queues seems to be mutually exclusive, such as dungeon finder and group finder. If a duel queue were implemented though, than a dual queue might be even more handy

If you like queueing go to a Theme Park!

I don't see the need. Duelling is free, easy and can be done just about anywhere. It gains the game nothing (of importance at any rate IMO) and it costs dev time which is better spent elsewhere. There's enough issues in dire need of fixing already. Let them spent their time on those.

Put a Wayshrine at Hammerdeath Arena so the intended Dueling location can actually be used by people wanting to Duel.

I'm honestly expecting Ranked Duelling to be the Q4 PvP thing they're talking about.

They've got the ToT ranked/unranked queue system already, and that's hat you'd need here. Add in the fact that we've had several threads lately talking about how it'd not be easy to convert PvErs into PvPers (and especially not casuals to PvPers), and that means that any new PvP content would need to pull from the existing playerbase, which would only lead to longer BG queues and emptier Cyro/IC zones. This would only pull two people from the PvP-sphere at a time for a quick duel, so it wouldn't have much of an effect on the existing PvP modes, while also allowing a quick PvP mode for those who only have a bit of time. Plus duelling is already in the game, so it's something that probably would take little dev time to make it 'official.'

If the duels would take place outside town limits then sure.