Not sure if this is the place to post this... But More open world style?

I was curious if there were more open world/flexible flow style hacks. And by this I mean like as a concept...

Imagining a world where the beginning city was in the center of a spider-web style map and you were free to go in one of the directions... Upon entering a route, the levels of the Pokemon are based in respect to your current team? Additionally, certain milestones/something would cause subsequent areas to change somewhat drastically. IE completing the more 'water' oriented branch and getting some mythical relic might cause flooding/heavy rain in the adjacent paths/all paths who knows.

Potentially make the starting city expandable as a means to use money and make HM's (or ideally items to replace HM's) unlockable depending on what you upgrade, as well as adding new encounters to the peripheral of the city?

This is just a random flow of thought. I've always wanted to try my hand at something like this but wondered if something like this existed already. Or what people thought of these concepts. I doubt I'm that original, and I doubt even more that this is entirely feasible.

EDIT: Didn't realize my signature apparently broke at some point. :v

The problem with open world hacks is the scale and the amount of branching that a hacker would have to account for. The Pokemon games' OW design also does not easily lend itself to an open world aesthetic, so it is difficult to map in that style and make it look good.

Basically, full open world hacks don't exist because they're a huge amount of work for a single person to do (above and beyond a full hack in the traditional style) because they have to account for all the branching the player can do, and the area design for this type of region would be difficult to make good and interesting for the player. I have seen attempts of these types of maps, and they end up empty and devoid of all character and interesting features. An open field with trees scattered around doesn't work for the Pokemon games like it works for BotW, for example. The gameplay and aesthetic of the Pokemon games just doesn't allow that to work.