Many, many things.
For me, the biggest issue is just making gaming overall more accessible to people experiencing conditions that otherwise make certain aspects of games more difficult to play for some individuals. Difficulty settings should just be obligatory in
all games, even those vaunted for their difficulty. Being able to change text size and color schemes to accommodate for people with vision issues should also be included.
Most importantly, controllers need to be produced that are just more accessible for people with physical disabilities. Stuff like this:
The Xbox Adaptive Controller is the best thing to happen to gaming in
decades and it's embarrassing that it took so long to become a concept. Both the pads on that controller are the equivalent of analog sticks, while separate buttons and switches can be plugged into the multitude of ports on the front to help position buttons in such a way that everyone can use them.
And Microsoft is the
only console manufacturer to produce this.
Technically you can use this controller on a Switch via the use of an adapter, but the Playstation consoles have no such accessibility. If you want to game on PS4/PS5, you'd better hope your hands and fingers can work around that controller.