I hate grinding the same quests over and over.
Since grinding is such and expected part of the game however, the idea here is to make a selection of randomized dungeons that are different each time you enter, thus making every run exciting and different since you never know what the layout will be or what obstacles you'll face.
You can have a number of them with different themes, so one might be dungeon, another a mansion, a third might be the demonweb, etc. Each with different possibilities, and each could be sold separately.
One aspect if this though, is that the whole dungeon will be the difficulty selected in terms of creature CRs and such, but as players go deeper, encounters have more enemies and happen more often, increasing the actual difficulty without increasing the numerical difficulty of DCs and saves and such. This also does two things, lets players explore longer without exiting and re-entering, and yet does make it a challenge to see how far they can go, especially if these dungeons have infinite depth. This challenge aspect can be enhanced by making rest shrines become ever rarer and consumables rare to non-existant as loot.
You might even have the Ultimate Growth difficulty, which has every level increase the number of things like champions, reaper rules (if playing epic levels), etc. And for this ultimate difficulty, loot is stored in a chest that is accessible only if the player leaves alive, but if they die and have to return to spirit binder, then they lose all the loot they gained.
I could do a whole design doc if the devs are interested at all.