What settings/genres are ripe for a new successful RPG?

[SimonMoon6]

Well if we go back to the grandaddy of isekai - A Connecticut Yankee in King Arthur’s Court, - the other problem is how do you stop modern knowledge overpowering and overrunning the setting?

Well, in that story, there was no magic. In D&D games, guns are usually way weaker than fireballs, so it doesn't make much sense to bother trying to invent gunpowder and guns and bombs when a fireball is way more effective. I mean, the one advantage is that mundane humans can use guns and stuff whereas only wizards (etc) can use fireballs, but one solution is to do silly Starfinder stuff like "Oh, sorry, that's a level 12 bomb and you're only 1st level, so you can't use it, even if the basic mechanics behind the bomb are the same as a level 1 bomb. Inexplicably, this bomb just doesn't work for you." (At least that's what I've heard Starfinder is like; I haven't actually read the rules.)

Re Isekai. As previously pointed out I think the main problem is not so much character creation, but what happens once the character is in world.

I have run manyself-insert games. I have also played in a few (but the ones I played in never lasted very long). Generally, I have found little problem with the game itself. The PCs are stuck in a world where the rules are different from what they know. Perhaps gunpowder doesn't even work in this world. It's not the real world after all. Try all the science you like, it's not gonna work. That's why everyone uses magic.

If this then seems like just another fantasy game with no isekai elements, keep in mind a few things: First, there is motivation. Self-insert PCs have different motivations than generic PCs, so that leads the game into different territories. Most noticeably with self-insert PCs, characters end up considering morality quite a bit more and can often disagree quite strongly. It's one thing for Blandy McBland the paladin to kill goblin babies for the greater good, but would RealWorld Guy kill them?

Also, a big thing that I don't see addressed is that self-insert PCs often (but not always) want to get back to the real world. So, that's a motivation that's unlike regular PCs. And then, we need to have questions like "Is it possible to get back to the real world and what are the rules behind doing so?" or "Does the story end when the PCs get back to the real world?"

For example, one such game that I was running in 3.0 (when it was new) was going to build up to a demon lord finding out about the "real world" that the PCs came from. He was going to invade with a huge army of demons who would mostly be immune to the mundane damage of the Earth's military might. Only the PCs stood any chance of their saving the real world from a demon invasion.

Basically, I see self-insert games as just a smaller less interesting version of a plane-hopping multiversal TORG style game (it doesn't have to have a full invasion like in TORG, but to be able to go to worlds with different rules is a big deal. And yes, TORG doesn't let the PCs do a lot of plane-hopping but that's because the other realities have come to Earth, so their rules are in various parts of Earth already.)

So, that's what I think the RPG market lacks. A *good* (so, for example, not RIFTS or GURPS) game that can handle different realities with different rules structures where things that work in one world will not work in another. And it needs to cover ways to travel between the various worlds.
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