Eh, I would hope a fan game would be a little more experimental, given how scared Gamefreak is to do anything different. Still wishing HM's weren't a thing and instead were items or if they remain HM's, simply having them allows any pokemon able to use them to do so without needing to "learn" it. Also wishing pokemon moves were instead learned and moved to a pool that you can swap your current active 4 moves with.

Point is the people who make those games use the ROMs as a way to "load" graphics and such therefor bypassing all the copyright issues. They don't distribute the ROMs, so you have to find them yourself pushing the liabilities on the users instead of them.