Another concept is cross-genre remakes of games.

One interesting example I thought of is the original SaGa (Final Fantasy Legend), but remade as an action game (specifically, a 2D sidescroller). Some aspects of this theoretical game:
* Assuming you're human, you can carry one weapon at a time. These weapons range from swords to guns to even a chainsaw.
* Said chainsaw has strange properties: It would fail to damage normal enemies, but would be an instant kill on bosses (assuming you manage to carry it that long).
* I'm thinking that the only saw to find would be in the tower before the fourth world. In world 4, it would allow you to just kill the Su-Zakus that come flying at you, but once you reach the first underground section, its inability to damage normal enemies would become apparent. (There would be a gun you can pick up right at that point, but Su-Zaku is immune to everything except the saw until the real fight, on top of a moving subway train.)
* If you're a monster, perhaps by eating meat dropped by the right monster may turn you into a bird, which would allow you to fly over areas and avoid platforming entirely. However, you would need to change into a sea creature for the game's one water level.

A self-aware artificial entity (whether AI, or bio-engineered, etc) that must be destroyed due to violation of IP laws. We've had body parts/implants and repossession of them, but an entire sentient being, I don't recall encountering.

Inspired by: Per Aspera's [branching, non-linear] story has some "close" elements.

Some game genre-soup is good. I can't recall a specific game that changed genre entirely during a remake (FF7 Remake is pretty darned close... not that I've drank from that rancid cistern; I'm certain some have happened). I don't like a lot of "beat em up" games, but Mortal Kombat had one that was good. It was MK fighting, but beat em up brawler levels and progression. It felt good to play.

Board games have had some cross-genre remakes that went successful. A sprawling game that was middling to successful, but gets redone as a lighter, card-focused game became a huge hit, etc. They're not too uncommon, actually. Sometimes both remain around with their fans, too.

There is Lufia: Curse of the Sinistrals. Lufia 2 is a strictly turn-based RPG (to an extent you don't see that often; even the visible enemies only move when you do, making avoiding them a puzzle rather than an action game). CotS, to my understanding, is an action game like the Ys games.

One could arguably put Ys: The Oath in Felghana here. The original was a sidescroller, while the remake is a 3D action game with a fixed camera.

On the other hand, there are remakes that aren't genre changing, but still change the game drastically. Looking only at Square Enix games, we have:
* Final Fantasy 3 DS. Completely new game mechanics under the hood.
* Final Fantasy 4 DS. Ditto.
* Romancing SaGa: Minstrel Song. Got rid of the whole "arts specific to weapon" mechanic, instead having arts being shared between weapons of the same type. Added LP from later SaGas. Added so many new mechanics.
* SaGa 3 DS: Perhaps the most drastic one. This is a remake of an RPG that got rid of levels and experience points, of all things.

Maybe not exactly what you're looking for, but:
https://www.gog.com/game/the_next_big_thing

Thanks of the link! Yeah, not quite what I was looking for, but appreciate it nonetheless. Thank you

Wow, haven't played a point-and-click since Indiana Jones and the Fate of Atlantis came out... but... might give this a try

I still think we lack racing games wirth RPG elements.

Most racing games with career modes don't focus on the cost side of the sport. Would love a mixture of racing game with career / team manager stuff. Like receiving offer for sponsors depending on driving performance, as well as testing offers to change teams or racing series.

I can see it happening with a Formula style game, which may not have much problems with licenses.

I think Pratchett's Discworld has been criminally overlooked in gaming. Only three point and click adventure games really. I want someone to pick up the license and make games in a few genres. First a turn based RPG similar to the South Park games. also an L.A. Noir style game in Ankh Morpork where you play as a recruit in the city watch. A business management sim where you can pay as C.M.O.T Dibbler and expand his sausage in a bun enterprise. There's so much subject matter across all genres in that world to be tapped into.

The other one that I've always wanted is a full PC remake of the old Steve Jackson Cars Wars table top game.

And then a faithful PC adaptation of the old Avalon Hill Squad Leader war game system...but this one is technically being worked on as Second Front under the revamped Microprose branding.

Another idea: Something like the video counterpart to Fantasia.

Each level is associated with some musical work, whether it be a public domain classical work, or a work composed specifically for the game. The levels are of the autoscroller or survival type, and the action is, in some ways, synchronized to the music. For example, when there's a crescendo, the game gets more intense, and when the music speeds up, watch out, because the game will be speeding up as well (maybe not *your* movement, but everything else would). Your goal, in this game, is to survive until the end of the piece. (Note that, for longer pieces, there may be mid-level checkpoints, typically in quieter parts of the work; if it's a multi-movement work, the movements might be separate stages.)

Cultural Relativism: The Game of the 21st Century

Not sure how I missed this one [post of yours] before. Check out the board game Spirit Island. (It's playable solo, too.)

There are procedurally-generated games, at least one schmup I'm aware of, that you feed your own music. It can never be as nice as hand-crafted though. I'd have to dig, but I could swear GOG has at least one actually.

I haven't played it, but: https://www.gog.com/game/symphony