Breath of Fire 3 hack, where EVERY character is a blank slate in terms of skills, which are either ALL learned through enemies or masters. Make some of the lesser masters more useful to add to the whole making your characters your way(through stat enhancements, etc). Still keep the characters having their own stat bonuses to make them what they originally are though, so that Nina for example could still be a stronger mage than say, Rei, if built the same way, but yeah. Honestly for this hack idea it'd probably even be fine just removing every character's skills and making them learnable through masters/monsters. Though honestly I think that might be difficult to do but who knows.
I really do hope someone picks up that Xenosaga idea though, it might actually make me able to stand to play it through, lol. I actually got cheat engine and tried to find the values but I wasn't even able to find the character base stats, which, yeah I'm not familiar at all with hacking when it doesn't involve game-specific tools, lol. I've also noticed there are literally NO PS2 hacks in the database, is there a reason?