What makes a good rom hack or Pokemon game for you? I want to make one but I need to know what gets people going in these games.

I want to make a game that's as open as possible. You can go everywhere you want, even if that means you're battling lv 60's with your lv. 5 starter. You should have near full freedom to travel anywhere and explore the world, without silly roadblocks and people telling you where you can go or where you can't go. But then it becomes hard to give the game a real purpose. If they can go anywhere, you know, eventually they go bored right? Now they've kinda been everywhere, and even though they didn't do all the quests or catch a lot of Pokemon, it's like, it's hard to make a story when you give players that kind of insane freedom. Anyways I'm rambling, go ahead.