I like these idea’s.
Although I see the fishing more as a true mmo idea … the idea of having small goals to work towards is a very good one. Back when I used to play wow, I equally had fun in completing side tasks as levelling professions and gaining achievements from it, as much as doing the main game.
After all, what are games, but giant dopamine inducers. So the more of these small targets you put in, the more people will have fun chasing those dopamine hits.
An endless dungeon could be good for this … a new deeper level is a new dopamine hit. A new achievement, a new goal to reach
And for those who strive for build perfection and speed, they could speed run it all they want and have ladders to keep track of that. Who can get the farthest, who can do it the fastest, who does it the first each season and so on … This would mean, that that endless dungeon would need to have a fixed layout, but finding optimal paths through that, is again a big thing for those elite players amongst us.
there are so many possibilities.