I started playing Rogue-likes as a substitute for Breath of the Wild. Apples to oranges, perhaps, but nonetheless, it's got me thinking.
There's an erotic rogue-like under construction called Noxico that has a lot of cool ideas. It's actually set up a bit more like Dwarf Fortress' Adventure Mode, with towns and wilderness, but also some dungeons set up here and there across the world with a rare item inside each. Though Noxico is incomplete, the framework exists to have sex with any character you meet in towns, and you can rape or get raped by monsters in the wilderness or in dungeons.
I also ended up playing my old rogue-like, Roguette, which was designed to be more arcade-like than rpg-like. In Roguette, you go through a linear dungeon with 5 elemental zones, the forest dungeon, cave dungeon, ice dungeon, magma dungeon and metal dungeon. Each zone is made up of 3 floors, with a boss at the end. Once you find and take The Orb at the end, you win. The original plan was to give all the enemies a huge power up and make you fight your way back to the beginning, but at the time, I decided that Roguette was as long of a game as it needed to be. In Roguette, you find articles of clothing in the dungeon as well, mostly designed to look sexy.
Some kind of combination of the two games could prove fruitful. Noxico's non-linearness can get annoying, since you have to wander around the wilderness looking for points of interest with no clues as to their location. Putting Noxico towns within a linear Roguette dungeon could fix things up. You'd probably get a different town at the beginning of each elemental zone, although I could also hide them somewhere within the dungeon to make finding them more rewarding. Or I could hide certain points of interest, shrines, shops, nightclubs, whatever, so that the main town is guaranteed easy, while the cool stuff you need to work for. If I really wanted to go nuts, I could make the game with more of a JRPG style world-map with "portals" to different dungeons or towns. I think I would still separate it into zones, so like the forest zone is its own complete world with forest towns and forest dungeons, and somewhere in it, you find a portal to the cave zone, which is its own world, yada yada.
Ideally I would want to think of more of a reason to have sex than just to have sex, like you have sex to complete quests, or fucking a monster restores your MP. But then, why not have sex just to have sex? Explore just to explore?
Doing a game with randomly generated characters, like Noxico's, would work best with live 3D graphics like Unity. I've been looking at Unity lately, and I saw that they've got a new (to me) tutorial for
cellular automata random dungeon making, which is especially neat because its natural look compliments my dungeonizer's blockier designs. I'm also eyeing Unity's
survival shooter tutorial as the combat system. I would probably try to make the shooting look more like a melee attack, but I might just give you a ray gun and make it sci-fi instead.
Challenge to this plan is dungeon diversity. Having to make a lot of monsters for every form of dungeon would be a major workload, and in 3D, a hefty file size. Preferable would be to keep everything vaguely humanoid looking, elves, ogres, werewolves, etc, and to re-use as much as I can. For example, if I do a goblin model, I want to have forest goblins, cave goblins, fire goblins, etc, and goblin enemies with different equipment, like a forest goblin archer, forest goblin warrior, forest goblin shaman, and so on. Likewise, it would be good for dungeons and towns to use the same models, for example, if there's an elf town in the forest zone, you also fight elf warriors in forest dungeons, except that this I think would decrease the benefit of exploring dungeons if there's nothing new to see there.