I spent some time thinking about what soloing content would feel like a good addition to the game in my opinion and here was what I came up with:
I don’t think solo dungeons would be a good idea without significant overhauling of the combat system and an immense amount of creativity.
All the classes in the game are very specialized to their roles. Dps have complex and interesting ways of dealing damage but lack any sort of depth in their ability to directly interact with enemies. Tanks on the other hand deal damage in very simplistic ways and don’t have a ton of ability to increase their damage output but have a ton of mobility and can engage with and adapt to enemies they are fighting. Healers can do both sort of okay but get most of their complexity through how they interact with other players in their party.
I think solo dungeons would push classes to express themselves in ways that lack depth and aren’t intuitive. I think it would make more sense to explore the intended roles of the classes but in slightly different ways than is usually tested by conventional dungeons.
I think the most simplistic boiled-down example of this would be like mini games. You just ask yourself how does this class express itself and build from there.
Maybe for scoundrel and ranger you have like an aim trainer. You could have progressively smaller, farther, and faster moving targets and you could put obstacles in the way to force them to arc/curve their shots.
Maybe for mage you have like speed casting. The game tells you random spells and you get progressively less time and harder spells. You could do almost the same thing with targets moving towards you progressively faster that can only be killed with the specific spells drawn on them.
Maybe for paladin or warrior you have an obstacle course with hazards and enemies that they need to run through as fast as possible.
Maybe for bard you make their songs get progressively faster and harder and if their combo meter hits 0 they lose.
All of these are random ideas off the top of my head but my greater point here is that I think to make solo content work it should engage players in a way that feel intuitive and flavorful for their class.